Thyroglobulin in serum as an indicator of iodine status during pregnancy

Thyroglobulin levels among iodine deficient pregnant women living in Northern Ireland

BACKGROUND

Iodine deficiency has re-emerged among pregnant cohorts in the UK. Thyroglobulin (Tg) is a protein produced uniquely by the thyroid gland which appears to mount a U-shaped response to extremes of iodine status. Tg has been suggested as an alternative marker for chronic iodine deficiency but the value of Tg in pregnancy has not been fully elucidated. A recent non-European study suggested a median Tg ≤10 µg/L with <3% of values >44 µg/L was indicative of sufficiency in the second trimester of pregnancy.

METHODS

We measured serum Tg levels in each trimester in 241 pregnant women living in Northern Ireland, a population with mild iodine deficiency at all stages of pregnancy as defined by urinary iodine concentration (UIC) and iodine: creatinine ratio (ICR). Women with Tg antibodies (6% in 1st trimester) were excluded.

RESULTS

The median UIC in this cohort was in the deficient range at 73, 94 and 117 µg/L in sequential trimesters (adequacy ≥ 150 µg/L). Corresponding median Tg levels were 19, 16 and 16 µg/L respectively. Median Tg for all samples was 17 μg/L (IQR 11-31) suggestive of iodine deficiency. Tg was >44 μg/L in 14.3%, 9.4% and 12.4% of women in sequential trimesters respectively. Women with either UIC/ICR below the cut-offs 150 µg/L and 150 µg/g creatinine had higher Tg concentrations in 1st and 2nd trimester (p < 0.01; p < 0.001) but not in 3rd trimester.

CONCLUSION

This study adds to the evolving evidence that Tg measurement is of value in reflecting iodine status in pregnancy.

[Critical analysis of the indicators of the nutritional status of iodine in individuals and populations: a systematic review]

The scope of this article is to evaluate the potentialities of indicators of the nutritional status of iodine in individuals or populations. The review was based on PRISMA. The search for articles occurred in January 2019, in the Pubmed, Scopus and LILACS databases, using the key words: indicators AND nutritional status AND iodine. The selection followed the stages of excluding the duplicates, reading the titles, abstracts and analyses in full. The methodological quality of the studies was evaluated by the Downs and Black instrument. A total of 178 studies were identified and 20 were included. Urinary Iodine Concentration (UIC) was analyzed in 65% of the studies and was considered the best indicator to evaluate the nutritional status of iodine in the population. Thyroglobulin was determined in 20% of the studies and reflected the pre-existing state of iodine. Thyroid stimulating hormone was verified in 45% of the articles and was important for the surveillance of iodine deficiency among newborns. Only one study evaluated capillary iodine, useful for analyzing long-term dietary intake. In the evaluation of methodological quality, the lowest score was 12 and the highest 16, in 17 possible points. The use of UIC is recommended for the diagnosis of deficiency and excess of iodine in the population.

Diagnosis of urinary tract infection based on symptoms: how are likelihood ratios affected by age? a diagnostic accuracy study

OBJECTIVES

The aim of this study was to investigate the impact of age on the diagnostic properties of typical symptoms of urinary tract infection (UTI) in women presenting in general practice with symptoms suggestive of UTI with significant bacteriuria as the reference standard.

DESIGN

Diagnostic accuracy study.

SETTING

General practice, Copenhagen, Denmark.

PARTICIPANTS

Adult 15 years or older. Women presenting in general practice with symptoms suggestive of UTI where urine was collected for investigation.

PRIMARY AND SECONDARY OUTCOME MEASURES

Accuracy of four symptoms of UTI (dysuria, frequency, urge and abdominal pain) in six different age groups.

RESULTS

90 practices included 1178 adult women. The prevalence of bacteriuria varied between 30% in women aged 30-44 years and 67% in women aged 75-89 years. The likelihood ratios for dysuria varied between age groups with the best performance in women aged 15-29 (positive likelihood ratio (pLR): 1.62 (1.30-1.94), negative likelihood ratio (nLR): 0.36 (0.19-0.54)) and women aged 30-44 (pLR: 1.74 (1.30-2.17), nLR: 0.48 (0.27-0.68)). CIs included or approximated one for the remaining symptoms in most age groups. When symptoms were combined to calculate post-test probabilities, the combined effect of the varying prevalence of bacteriuria and the varying diagnostic values resulted in a large variation of the post-test probabilities between age groups.

CONCLUSIONS

The diagnostic value of symptoms of UTI as well as the prevalence of bacteriuria in women presenting to general practice with suspected UTI vary between age groups with considerable clinical implications. Diagnostic studies should take demographics such as age into consideration.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov: NCT02698332.

Iodine, Thyroglobulin and Thyroid Gland

Iodine is essential in the biosynthesis of thyroid hormones that affect metabolic processes in the organism from the prenatal state to the elderly. The immediate indicator of iodine intake is the concentration of iodine in urine, but the indicator of iodine intake in the longer term of several months is thyroglobulin (Tg). Tg negatively correlated with increasing intake of iodine in population that do not suffer from thyroid disease, while a more than adequate to excessive iodine intake leads to an increase in Tg. The dependence of Tg on iodine can be described by a U-shaped curve. Thyroglobulin in serum is elevated in thyroid disease mainly in hyperthyroidism (diagnosis E05 of WHO ICD-10 codes) and in goiter (diagnosis E04 of WHO ICD-10 codes). Tg values decrease below 20 µg/l after effective treatment of patients with thyroid disease. Thyroglobulin may thus be an indicator of thyroid stabilization and the success of the thyroid gland treatment.

Current iodine nutrition status in Poland (2017): is the Polish model of obligatory iodine prophylaxis able to eliminate iodine deficiency in the population?

OBJECTIVE

The monitoring of the populations' iodine status is an essential part of successful programmes of iodine deficiency elimination. The current study aimed at the evaluation of current iodine nutrition in school children, pregnant and lactating women as a marker of the effectiveness and sustainability of mandatory iodine prophylaxis in Poland.

DESIGN

The following iodine nutrition indicators were used: urinary iodine concentration (UIC) (all participants) and serum thyroglobulin (pregnant and lactating women).

SETTING

The study was conducted in 2017 within the National Health Programme in five regions of Poland.

PARTICIPANTS

The research included 300 pregnant women, 100 lactating women and 1000 school children (aged 6-12 years).

RESULTS

In pregnant women, median UIC was 111·6 µg/l; there was no significant difference in median UIC according to the region of residence. In 8 % of pregnant women, thyroglobulin level was >40 ng/ml (median thyroglobulin 13·3 ng/ml). In lactating women, median UIC was 68·0 µg/l. A significant inter-regional difference was noted (P = 0·0143). In 18 % of breastfeeding women, thyroglobulin level was >40 ng/ml (median thyroglobulin 18·5 ng/ml). According to the WHO criteria, the investigated sample of pregnant and lactating women was iodine-deficient. Median UIC in school children was 119·8 µg/l (with significant inter-regional variation; P = 0·0000), which is consistent with iodine sufficiency. Ninety-four children (9·4 %) had UIC < 50 µg/l.

CONCLUSIONS

Mandatory iodisation of household salt in Poland has led to a sustainable optimisation of iodine status in the general population. However, it has failed to assure adequate iodine nutrition during pregnancy and lactation.

The Effects of Iodine Supplementation in Pregnancy on Iodine Status, Thyroglobulin Levels and Thyroid Function Parameters: Results from a Randomized Controlled Clinical Trial in a Mild-to-Moderate Iodine Deficiency Area

BACKGROUND

Iodine supplementation during pregnancy in areas with mild-to-moderate iodine deficiency is still debated.

METHODS

A single-center, randomized, single-blind and placebo-controlled (3:2) trial was conducted. We enrolled 90 women before 12 weeks of gestation. From enrollment up until 8 weeks after delivery, 52 women were given an iodine supplement (225 ug/day, potassium iodide tablets) and 38 were given placebo. At recruitment (T0), in the second (T1) and third trimesters (T2), and 8 weeks after delivery (T3), we measured participants' urinary iodine-to-creatinine ratio (UI/Creat), thyroid function parameters (thyroglobulin (Tg), TSH, FT3, and FT4), and thyroid volume (TV). The newborns' urinary iodine concentrations were evaluated in 16 cases.

RESULTS

Median UI/Creat at recruitment was 53.3 ug/g. UI/Creat was significantly higher in supplemented women at T1 and T2. Tg levels were lower at T1 and T2 in women with UI/Creat ≥ 150 ug/g, and in the Iodine group at T2 (p = 0.02). There was a negative correlation between Tg and UI/Creat throughout the study (p = 0.03, r = -0.1268). A lower TSH level was found in the Iodine group at T3 (p = 0.001). TV increased by +Δ7.43% in the Iodine group, and by +Δ11.17% in the Placebo group. No differences were found between the newborns' TSH levels on screening the two groups.

CONCLUSION

Tg proved a good parameter for measuring iodine intake in our placebo-controlled series. Iodine supplementation did not prove harmful to pregnancy in areas of mild-to-moderate iodine deficiency, with no appreciable harmful effect on thyroid function.

Iodine deficiency in pregnant women in Sweden: a national cross-sectional study

Purpose

Voluntary salt iodization at 50 mg/kg salt ensures adequate iodine nutrition in Swedish school-aged children, but iodine status in pregnant women is uncertain.

Methods

We conducted a cross-sectional national study of 743 pregnant women, at median gestational age of 23 weeks (IQR 9, 38), recruited from maternal health care centers. We measured: urinary iodine concentration (UIC) and urinary creatinine concentration in spot urine samples; thyroglobulin (Tg), thyroid-stimulating hormone (TSH), and total thyroxine (tT4) on dried blood spots (DBS); and thyreoperoxidase antibodies in serum samples. Data on dietary supplement use were obtained, and women were classified as supplement users (consuming multivitamins containing ≥ 150 µg iodine/day) and non-supplement users (no supplements or < 150 µg iodine/day from supplements).

Results

Overall median UIC [bootstrapped 95% confidence interval (CI)] was 101 µg/L (95, 108; n = 737): 149 µg/L (132, 164) in supplement users (n = 253) and 85 µg/L (79, 92) in non-supplement users (n = 440) (p < 0.001). Overall geometric mean DBS-Tg (95% CI) was 22.1 μg/L (20.8, 23.5; n = 675) and the prevalence of elevated DBS-Tg was 19%. DBS-Tg was lower in supplement users (n = 229) than in non-supplement users (n = 405) (19.1 vs 24.4 μg/L, p < 0.001). DBS-TSH, DBS-tT4, and S-TPOab positivity did not differ between the two groups.

Conclusions

Pregnant women in Sweden have inadequate iodine nutrition. Women not taking iodine supplements containing ≥ 150 µg iodine/day are affected by mild iodine deficiency and are at higher risk for increased thyroid activity, while maintaining euthyroidism. Iodine intake should be improved in women both before and after conception by promotion of iodized salt instead of non-iodized salt. We urge regular monitoring of iodine status in the general Swedish population, as well as in risk groups.

Role of iodine-containing multivitamins during pregnancy for children's brain function: protocol of an ongoing randomised controlled trial: the SWIDDICH study

INTRODUCTION

Iodine is essential for normal brain development. Moderate and severe fetal iodine deficiency results in substantial to serious developmental delay in children. Mild iodine deficiency in pregnancy is associated with neurodevelopmental deficits in the offspring, but evidence from randomised trials is lacking. The aim of the Swedish Iodine in Pregnancy and Development in Children study is to determine the effect of daily supplementation with 150 µg iodine during pregnancy on the offspring's neuropsychological development up to 14 years of age.

METHODS AND ANALYSIS

Thyroid healthy pregnant women (n=1275: age range 18-40 years) at ≤12 weeks gestation will be randomly assigned to receive multivitamin supplements containing 150 µg iodine or non-iodine-containing multivitamin daily throughout pregnancy. As a primary outcome, IQ will be measured in the offspring at 7 years (Wechsler Intelligence Scale for Children-V). As secondary outcomes, IQ will be measured at 3.5 and 14 years, psychomotor development at 18 months and 7 years, and behaviour at 3.5, 7 and 14 years. Iodine status (urinary iodine concentration) will be measured during pregnancy and in the offspring at 3.5, 7 and 14 years. Thyroid function (thyroid hormones, thyroglobulin), and deiodinase type 2 polymorphisms will be measured during pregnancy and in the offspring at 7 and 14 years. Structural MRI or other relevant structural or functional brain imaging procedures will be performed in a subgroup of children at 7 and 14 years. Background and socioeconomic information will be collected at all follow-up times.

ETHICS AND DISSEMINATION

This study is approved by the Ethics Committee in Göteborg, Sweden (Diary numbers: 431-12 approved 18 June 2012 (pregnancy part) and 1089-16 approved 8 February 2017 (children follow-up)). According to Swedish regulations, dietary supplements are governed by the National Food Agency and not by the Medical Product Agency. Therefore, there is no requirement for a monitoring committee and the National Food Agency does not perform any audits of trial conduct. The trial will be conducted in accordance with the Declaration of Helsinki. The participating sites will be contacted regarding important protocol changes, both orally and in writing, and the trial registry database will be updated accordingly. Study results will be presented at relevant conferences, and submitted to peer-reviewed journals with open access in the fields of endocrinology, paediatrics and nutrition. After the appropriate embargo period, the results will be communicated to participants, healthcare professionals at the maternal healthcare centres, the public and other relevant groups, such as the national guideline group for thyroid and pregnancy and the National Food Agency.

TRIAL REGISTRATION NUMBER

NCT02378246; Pre-results.

Automated Flow Cytometry: An Alternative to Urine Culture in a Routine Clinical Microbiology Laboratory?

The urine culture is the "gold standard" for the diagnosis of urinary tract infections (UTI) but constitutes a significant workload in the routine clinical laboratory. Due to the high percentage of negative results, there is a need for an efficient screening method, with a high negative predictive value (NPV) that could reduce the number of unnecessary culture tests. With the purpose of improving the efficiency of laboratory work, several methods for screening out the culture-negative samples have been developed, but none of them has shown adequate sensitivity (SE) and high NPV. Many authors show data about the efficacy of flow cytometry in the routine clinical laboratory. The aim of this article is to review and discuss the current literature on the feasibility of urine flow cytometry (UFC) and its utility as an alternative analytical technique in urinalysis.

Iodine Storage and Metabolism of Mild to Moderate Iodine-Deficient Pregnant Rats

BACKGROUND

Severe iodine deficiency during pregnancy results in neurodevelopmental disorders in children, while the consequences of mild to moderate iodine deficiency (MMID) are uncertain. The concentration of iodine in the thyroid is the most accurate indicator of iodine nutrition. This study aimed to evaluate whether the iodine stores in the thyroid cover the needs of the mother and the fetus in iodine-sufficient and MMID conditions by inductively coupled plasma-mass spectrometry.

METHODS

One hundred four-week-old female Wistar rats were randomly divided into MMID (low iodine intake [L]) and normal (normal iodine intake [N]) groups. The rats were fed for the next three months, and after pregnancy they were further divided into two subgroups, respectively: low iodine pregnancy (LP) and low iodine pregnancy with iodine supplement (LP+), and normal iodine intake pregnancy (NP) and normal iodine intake pregnancy with iodine supplement (NP+). The iodine intake of pregnant rats in the NP+ and LP+ groups was twice as much as in the NP and LP groups. The rats were sacrificed on gestational day 15 and postnatal day 7. The iodine concentration in the thyroid of the maternal and newborn rats, maternal serum, placenta, and amniotic fluid were determined by inductively coupled plasma-mass spectrometry.

RESULTS

The concentration of iodine in the thyroid of the N group was significantly higher than that in the L group before pregnancy. The concentration of iodine in the maternal thyroids of the LP group decreased during pregnancy, whereas that of the NP group did not change significantly. There was no significant difference in the iodine concentration in the thyroid of mothers and offspring between the NP and NP+ groups, but it was significant between LP and LP+ groups. The concentration of iodine in amniotic fluid was significantly different between the four groups.

CONCLUSION

There is sufficient iodine storage in the thyroid of maternal rats with normal iodine intake during pregnancy, and there is no need for iodine supplementation. However, iodine stores are insufficient in rats with MMID. Iodine supplementation can increase the iodine concentration in the thyroid of maternal rats with MMID and their offspring, as well as in the amniotic fluid during pregnancy.

Clinical accuracy of point-of-care urine culture in general practice

OBJECTIVE

To assess the clinical accuracy (sensitivity (SEN), specificity (SPE), positive predictive value and negative predictive value) of two point-of-care (POC) urine culture tests for the identification of urinary tract infection (UTI) in general practice.

DESIGN

Prospective diagnostic accuracy study comparing two index tests (Flexicult™ SSI-Urinary Kit or ID Flexicult™) with a reference standard (urine culture performed in the microbiological department).

SETTING

General practice in the Copenhagen area patients. Adult female patients consulting their general practitioner with suspected uncomplicated, symptomatic UTI.

MAIN OUTCOME MEASURES

(1) Overall accuracy of POC urine culture in general practice. (2) Individual accuracy of each of the two POC tests in this study. (3) Accuracy of POC urine culture in general practice with enterococci excluded, since enterococci are known to multiply in boric acid used for transportation for the reference standard. (4) Accuracy based on expert reading of photographs of POC urine cultures performed in general practice. Standard culture performed in the microbiological department was used as reference standard for all four measures.

RESULTS

Twenty general practices recruited 341 patients with suspected uncomplicated UTI. The overall agreement between index test and reference was 0.76 (CI: 0.71-0.80), SEN 0.88 (CI: 0.83-0.92) and SPE 0.55 (CI: 0.46-0.64). The two POC tests produced similar results individually. Overall agreement with enterococci excluded was 0.82 (0.77-0.86) and agreement between expert readings of photographs and reference results was 0.81 (CI: 0.76-0.85).

CONCLUSIONS

POC culture used in general practice has high SEN but low SPE. Low SPE could be due to both misinterpretation in general practice and an imperfect reference standard. Registration number: ClinicalTrials.gov NCT02323087.

Development and validation of a condition-specific diary to measure severity, bothersomeness and impact on daily activities for patients with acute urinary tract infection in primary care

BACKGROUND

Urinary tract infection (UTI) is a common condition in primary care. Patient-reported outcome measures (PROMs) are crucial in the evaluation of interventions to improve diagnosis, treatment and prognosis of UTI. The aim of this study was to identify an existing condition-specific PROM to measure symptom severity, bothersomeness and impact on daily activities for adult patients with suspected urinary tract infection in primary care; or, in the absence of such a PROM, to test items identified from existing PROMs for coverage and relevance in single and group interviews and to psychometrically validate the resulting PROM.

METHODS

The literature was searched for existing PROMs covering the three domains. Items from the identified PROMs were tested in single and group interviews. The resulting symptom diary was psychometrically validated using the partial credit Rasch model for polytomous items in a cohort of 451 women participating in two studies regarding UTI.

RESULTS

No existing PROM fulfilled the inclusion criteria. Content validation resulted in one domain concerning symptom severity (18 items), one concerning bothersomeness (18 items), and one concerning impact on daily activities (7 items). Psychometrical validation resulted in four dimensions in each of the first two domains and one dimension in the third domain.

CONCLUSIONS

Domains were not unidimensional, which meant that we identified dimensions of patient-experienced UTI that differed substantially from those previously found. We recommend that future studies on UTI, in which PROMs are to be used, should ensure high content validity of their outcome measures and unidimensionality of the included dimensions.

Thyroglobulin as a Functional Biomarker of Iodine Status in a Cohort Study of Pregnant Women in the United Kingdom

BACKGROUND

Though iodine deficiency in pregnancy is a matter of public-health concern, a functional measure of iodine status is lacking. The thyroid-specific protein thyroglobulin (Tg), which reflects thyroid size, has shown promise as a functional measure in studies of children and adults, but data in pregnancy are sparse. In a cohort of mildly to moderately iodine-deficient pregnant women, this study aimed to explore whether serum Tg is a sensitive functional biomarker of iodine status and to examine longitudinal change in Tg with gestational age.

METHOD

A total of 230 pregnant women were recruited at an antenatal clinic at 12 weeks of gestation to the Selenium in PRegnancy INTervention study, in Oxford, United Kingdom. Repeated measures of urinary iodine-to-creatinine ratio, serum thyrotropin (TSH), and Tg at 12, 20, and 35 weeks of gestation were made. Women were dichotomized by their iodine-to-creatinine ratio (<150 or ≥150 μg/g) to group them broadly as iodine deficient or iodine sufficient. Women with thyroid antibodies were excluded; data and samples were available for 191 women.

RESULTS

Median Tg concentrations were 21, 19, and 23 μg/L in the first, second, and third trimesters, respectively. In a linear mixed model, controlling for confounders, Tg was higher in the <150 μg/g group than it was in the ≥150 μg/g group (p < 0.001) but there was no difference in TSH (p = 0.27). Gestational week modified the effect of iodine status on TSH (p = 0.01) and Tg (p = 0.012); Tg did not increase with gestational week in the ≥150 μg/g group, but it did in the <150 μg/g group, and TSH increased more steeply in the <150 μg/g group.

CONCLUSIONS

Low iodine status (<150 μg/g) in pregnancy is associated with higher serum Tg, suggesting that the thyroid is hyperstimulated by iodine deficiency, which causes it to enlarge. Tg is a more sensitive biomarker of iodine status in pregnancy than is TSH.

Gestation-specific changes in maternal thyroglobulin during pregnancy and lactation in an iodine-sufficient region in China: a longitudinal study

OBJECTIVES

To describe the changes in thyroglobulin (Tg) based upon gestational and postpartum concentrations in healthy pregnant women from an iodine-sufficient region in China, and to evaluate the use of Tg as a biomarker for iodine-sufficient pregnant women.

DESIGN

A longitudinal study of Tg change in normal pregnant women from an iodine-sufficient region.

PATIENTS AND MEASUREMENTS

Blood and urine samples were obtained from 133 pregnant women. Urinary iodine concentration (UIC) was measured using an ammonium persulfate method. Serum iodine concentration was required by inductively coupled plasma mass spectrometry (ICP-MS). Serum thyroid-stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), total thyroxine (TT4), total triiodothyronine (TT3), antithyroid peroxidase antibody (TPOAb), antithyroglobulin antibody (TgAb) and Tg were measured using an electrochemiluminescence immunoassay.

RESULTS

Thyroglobulin concentrations were higher in early pregnancy (pregnancy at 8 weeks vs nonpregnancy: 11·42 ng/ml vs 8·8 ng/ml, P < 0·01) and maintained a stable level, and then increased greatly at the 36th week. After delivery, Tg decreased to nonpregnant levels. During pregnancy, maternal Tg was not correlated with thyroid function, UIC or urine iodine-creatinine ratio (UI/Cr). Cord blood Tg was much higher compared to maternal Tg levels at the 36w (57·34 vs 14·86 ng/ml, P < 0·001) and correlated positively with cord FT4 (r = 0·256, P < 0·05), cord TT4 (r = 0·263, P < 0·05) and maternal UI/Cr at 36w (r = -0·214, P < 0·05).

CONCLUSIONS

Our work demonstrates that Tg is elevated during pregnancy, and the effect of pregnancy should be taken into consideration when Tg is used as a biomarker for the iodine status. Cord blood Tg is much higher than maternal Tg levels at the 36w and is correlated with maternal iodine status.

Dried Blood Spot Thyroglobulin as a Biomarker of Iodine Status in Pregnant Women

CONTEXT

Thyroglobulin (Tg) could be a sensitive biomarker of iodine nutrition in pregnant women (PW). A dried blood spot (DBS) assay would simplify collection and transport in field studies.

OBJECTIVES

Our aims were to (1) establish and test a reference range for DBS-Tg in PW; (2) determine whether co-measurement of Tg antibodies (Abs) is necessary to define population iodine status.

DESIGN, SETTING, AND PARTICIPANTS

Standardized cross-sectional studies of 3870 PW from 11 countries. For the DBS-Tg reference range, we included TgAb-negative PW (n = 599) from 3 countries with sufficient iodine intake.

MAIN OUTCOME MEASURES

We measured the urinary iodine concentration and DBS thyroid-stimulating hormone, total thyroxin, Tg, and TgAb.

RESULTS

In the reference population, the median DBS-Tg was 9.2 μg/L (95% confidence interval, 8.7 to 9.8 μg/L) and was not significantly different among trimesters. The reference range was 0.3 to 43.5 μg/L. Over a range of iodine intake, the Tg concentrations were U-shaped. Within countries, the median DBS-Tg and the presence of elevated DBS-Tg did not differ significantly between all PW and PW who were TgAb-negative.

CONCLUSIONS

A median DBS-Tg of ∼10 μg/L with <3% of values ≥44 μg/L indicated population iodine sufficiency. Concurrent measurement of TgAb did not appear necessary to assess the population iodine status.

Performance Evaluation and Comparison of the Fully Automated Urinalysis Analyzers UX-2000 and Cobas 6500

OBJECTIVE

To evaluate and compare the performances of the automated urinalysis devices UX-2000 and Cobas 6500.

METHOD

A total of 258 urine specimens were collected from the routine specimen workload. We analyzed all specimens on both automated instruments and recorded the turnaround time from each method. Physical, chemical, and sedimentary urine components were compared between the automated and the manual method for each analyzer.

RESULTS

The correlation of urine physical/chemical properties between the 2 instruments was excellent. The Cobas 6500 instrument demonstrated a higher level of agreement for red blood cells (Cobas 6500:R= 0.94; UX-2000:R= 0.78) and white blood cells (Cobas 6500:R= 0.95; UX-2000:R= 0.85). The UX-2000 demonstrated higher sensitivity for small round cells, hyaline casts, pathological casts, and bacteria. The median turnaround time was 1.5 minutes and 8.5 minutes for the Cobas 6500 and UX-2000, respectively.

CONCLUSIONS

The 2 devices showed similar performance in technical evaluation; they each reduce workload and increase time saving. However, manual examination by technicians is recommended for pathological specimens.

Urinary iodine concentration identifies pregnant women as iodine deficient yet school-aged children as iodine sufficient in rural Niger

OBJECTIVE

To assess iodine status among pregnant women in rural Zinder, Niger and to compare their status with the iodine status of school-aged children from the same households.

DESIGN

Seventy-three villages in the catchment area of sixteen health centres were randomly selected to participate in the cross-sectional survey.

SETTING

Salt iodization is mandatory in Niger, requiring 20-60 ppm iodine at the retail level.

SUBJECTS

A spot urine sample was collected from randomly selected pregnant women (n 662) and one school-aged child from the same household (n 373). Urinary iodine concentration (UIC) was assessed as an indicator of iodine status in both groups. Dried blood spots (DBS) were collected from venous blood samples of pregnant women and thyroglobulin (Tg), thyroid-stimulating hormone and total thyroxine were measured. Iodine content of household salt samples (n 108) was assessed by titration.

RESULTS

Median iodine content of salt samples was 5·5 ppm (range 0-41 ppm), 98 % had an iodine content 40 µg/l.

CONCLUSIONS

In this region of Niger, most salt is inadequately iodized. UIC in pregnant women indicated iodine deficiency, whereas UIC of school-aged children indicated marginally adequate iodine status. Thus, estimating population iodine status based solely on monitoring of UIC among school-aged children may underestimate the risk of iodine deficiency in pregnant women.

Trimester-specific thyroid hormone reference ranges in Sudanese women

BACKGROUND

Trimester-specific reference ranges for T3, T4, and TSH need to be established in different communities. Neither Sudan nor other African countries have established trimester-specific reference ranges for TSH, free T3 (FT3), and free T4 (FT4) in healthy pregnant women. This study aimed to establish trimester-specific reference ranges for TSH, FT3, and FT4 in healthy pregnant Sudanese women.

RESULTS

We performed a longitudinal study, which included 63 women with singleton pregnancies who were followed since early pregnancy until the third trimester. The study was performed in Saad Abu-Alela Hospital, Khartoum, Sudan, during January to October 2014. An equal number of age- and parity-matched non-pregnant women were enrolled as a control group. Basic clinical and obstetrics data were gathered using questionnaires. TSH, FT3, and FT4 levels were measured. Median (5th-95th centile) values of TSH, FT3, and FT4 were 1.164 IU/ml (0.079-2.177 IU/ml), 4.639 nmol/l (3.843-6.562 nmol/l), and 16.86 pmol/l (13.02-31.48 pmol/l) in the first trimester. Median values of TSH, FT3, and FT4 were 1.364 IU/ml (0.540-2.521 IU/ml), 4.347 nmol/l (3.425-5.447 nmol/l), and 13.51 pmol/l (11.04-31.07 pmol/l) in the second trimester. These values were 1.445 IU/ml (0.588-2.460 IU/ml), 4.132 nmol/l (3.176-5.164 nmol/l), and 12.87 pmol/l (9.807-23.78 pmol/l) in the third trimester, respectively. TSH levels increased throughout the trimesters. FT3 and FT4 levels were significantly higher in the first trimester compared with the second and third trimesters. TSH, FT3, and FT4 levels were significantly lower in pregnant women compared with non-pregnant women (P < 0.001).

CONCLUSIONS

The present study is the first to establish trimester-specific reference ranges of TSH, FT3, and FT4 in Sudanese women with normal pregnancies. Our results suggest that pregnancy is likely to suppress TSH, T3, and T4 levels in healthy women.

Pentafluorobenzyl bromide-A versatile derivatization agent in chromatography and mass spectrometry: I. Analysis of inorganic anions and organophosphates

Pentafluorobenzyl bromide (PFB-Br) is a versatile derivatization agent. It is widely used in chromatography and mass spectrometry since several decades. The bromide atom is largely the single leaving group of PFB-Br. It is substituted by wide a spectrum of nucleophiles in aqueous and non-aqueous systems to form electrically neutral, in most organic solvents soluble, generally thermally stable, volatile, strongly electron-capturing and ultraviolet light-absorbing derivatives. Because of these greatly favoured physicochemical properties, PFB-Br emerged an ideal derivatization agent for highly sensitive analysis of endogenous and exogenous substances including various inorganic and organic anions by electron capture detection or after electron-capture negative-ion chemical ionization in GC-MS. The present article attempts an appraisal of the utility of PFB-Br in analytical chemistry. It reviews and discusses papers dealing with the use of PFB-Br as the derivatization reagent in the qualitative and quantitative analysis of endogenous and exogenous inorganic anions in various biological samples, notably plasma, urine and saliva. These analytes include nitrite, nitrate, cyanide and dialkyl organophosphates. Special emphasis is given to mass spectrometry-based approaches and stable-isotope dilution techniques.

Serum Thyroglobulin Concentration Is a Weak Marker of Iodine Status in a Pregnant Population with Iodine Deficiency

OBJECTIVE

To assess the reliability of thyroglobulin (Tg) as a marker of iodine status during pregnancy.

DESIGN

299 women aged 30.5 ± 4.8 years (mean ± SD) were studied.

METHODS

In every subject, we measured urinary iodine concentration (UIC), serum thyrotropin (TSH), Tg, free thyroxine (fT4), Tg autoantibodies (TgAbs) and human chorionic gonadotropin (hCG) levels. We excluded samples with increased TgAbs from the analysis.

RESULTS

According to WHO criteria, the study population was iodine deficient in every trimester. Serum Tg levels did not differ during the three trimesters of pregnancy. Serum hCG levels fell significantly as pregnancies advanced. A weak, significantly negative correlation (limited to the 3rd trimester) was found between Tg and UIC (ρ = -0.187, p = 0.039). Serum fT4 decreased as pregnancies advanced and TSH increased. Serum fT4 was negatively correlated with TSH (ρ = -0.161, p = 0.006) and positively with hCG (ρ = +0.165, p = 0.005). The multiple regression equation of Tg based on hCG, TSH, UIC and trimester of pregnancy was significant but weak (F = 4.057, p = 0.003; R(2) = 0.055), with hCG as a significant predictor Tg (p for log hCG = 0.041).

CONCLUSIONS

Tg cannot be considered as a valid marker of iodine deficiency in pregnancy, at least in a mildly iodine-deficient environment. Further studies in a larger patient cohort with differences in iodine status, as well as studies on Tg changes after improving iodine status in pregnant women, are needed in order to corroborate these results.

Urine sampling techniques in symptomatic primary-care patients: a diagnostic accuracy review

Background

Choice of urine sampling technique in urinary tract infection may impact diagnostic accuracy and thus lead to possible over- or undertreatment. Currently no evidencebased consensus exists regarding correct sampling technique of urine from women with symptoms of urinary tract infection in primary care. The aim of this study was to determine the accuracy of urine culture from different sampling-techniques in symptomatic non-pregnant women in primary care.

Methods

A systematic review was conducted by searching Medline and Embase for clinical studies conducted in primary care using a randomized or paired design to compare the result of urine culture obtained with two or more collection techniques in adult, female, non-pregnant patients with symptoms of urinary tract infection. We evaluated quality of the studies and compared accuracy based on dichotomized outcomes.

Results

We included seven studies investigating urine sampling technique in 1062 symptomatic patients in primary care. Mid-stream-clean-catch had a positive predictive value of 0.79 to 0.95 and a negative predictive value close to 1 compared to sterile techniques. Two randomized controlled trials found no difference in infection rate between mid-stream-clean-catch, mid-stream-urine and random samples.

Conclusions

At present, no evidence suggests that sampling technique affects the accuracy of the microbiological diagnosis in non-pregnant women with symptoms of urinary tract infection in primary care. However, the evidence presented is in-direct and the difference between mid-stream-clean-catch, mid-stream-urine and random samples remains to be investigated in a paired design to verify the present findings.

Electronic supplementary material

The online version of this article (doi:10.1186/s12875-016-0465-4) contains supplementary material, which is available to authorized users.

Iodine status in the Nordic countries - past and present

Background

Adequate iodine nutrition is dependent on ground water content, seafood, and, as many countries use iodized cow fodder, dairy products. In most countries, salt fortification programs are needed to assure adequate iodine intake.

Objectives

The objectives are threefold: 1) to describe the past and present iodine situation in the Nordic countries, 2) to identify important gaps of knowledge, and 3) to highlight differences among the Nordic countries’ iodine biomonitoring and fortification policies.

Design

Historical data are compared with the current situation. The Nordic countries’ strategies to achieve recommended intake and urine iodine levels and their respective success rates are evaluated.

Results

In the past, the iodine situation ranged from excellent in Iceland to widespread goiter and cretinism in large areas of Sweden. The situation was less severe in Norway and Finland. According to a 1960 World Health Organization (WHO) report, there were then no observations of iodine deficiency in Denmark. In Sweden and Finland, the fortification of table salt was introduced 50–75 years ago, and in Norway and Finland, the fortification of cow fodder starting in the 1950s helped improve the population's iodine status due to the high intake of milk. In Denmark, iodine has been added to household salt and salt in bread for the past 15 years. The Nordic countries differ with regard to regulations and degree of governmental involvement. There are indications that pregnant and lactating women, the two most vulnerable groups, are mildly deficient in iodine in several of the Nordic countries.

Conclusion

The Nordic countries employ different strategies to attain adequate iodine nutrition. The situation is not optimal and is in need of re-evaluation. Iodine researchers, Nordic national food administrations, and Nordic governmental institutions would benefit from collaboration to attain a broader approach and guarantee good iodine health for all.

Evaluation of an Image Analysis Device (APAS) for Screening Urine Cultures

While advancements have been made in some areas of pathology with diagnostic materials being screened using image analysis technologies, the reporting of cultures from agar plates remains a manual process. We compared the results for 2,163 urine cultures read by a reference panel of microbiologists, by the routine laboratory process, and by an automated plate reading system, APAS (LBT Innovations Ltd., South Australia). APAS detected colonies with a sensitivity of 99.1% and a specificity of 99.3% on blood agar, while on MacConkey agar, the colony detection sensitivity was 99.4% with a specificity of 99.3%. The device's ability to enumerate growth had an accuracy of 89.2%, and the morphological identification of colonies showed a high level of performance for the colony types typical of Escherichia coli and other enteric bacilli. On blood agar, lactose-fermenting colonies were morphologically identified with a sensitivity of 98.9%, while on MacConkey agar they were identified with a sensitivity of 99.2%. In this first clinical evaluation, APAS demonstrated high performance in the detection, enumeration, and colony classification of isolates compared with that for conventional plate-reading methods. The device found all cases reported by the laboratory and detected the most commonly encountered organisms found in urinary tract infections.

Phylogenetic groups of Escherichia coli strains from patients with urinary tract infection in Iran based on the new Clermont phylotyping method

OBJECTIVES

In 2013, Clermont classified E. coli strains into eight phylogenetic groups using a new quadruplex PCR method. The aims of this study were to identify the phylogenetic groups of E. coli based on this method and to assess their antibiotic resistance patterns in Bushehr, Iran.

METHODS

In this cross-sectional study, 140 E. coli isolates were subjected to phylogenetic typing by a quadruplex PCR method. Antimicrobial susceptibility testing was performed by disk diffusion method.

RESULTS

Phylogenetic group B2 was most predominant (39.3%), followed by unknown (27.1%), E (9.3%), C and clade I (each 6.4%), B1 (5%), F and D (each 2.9%), and A (0.7%). The most common antibiotic resistance was related to amoxicillin (82.1%) and the least to meropenem (0.7%). 82.14% of isolates were multiple drug resistant (MDR). Antibiotic resistance was mainly detected in group B2 (50%).

CONCLUSIONS

Our findings showed the high prevalence of MDR E. coli isolates with dominance of group B2. About 25% of E. coli isolates belong to the newly described phylogroups C, E, F, and clade I. Such studies need to be done also in other regions to provide greater understanding of the antibiotic resistance pattern and the prevalences of different phylogenetic groups.

Thyroglobulin as a biomarker of iodine deficiency: a review

BACKGROUND

Thyroglobulin, produced exclusively by the thyroid gland, has been proposed to be a more sensitive biomarker of iodine status than thyrotropin or the thyroid hormones triiodothyronine and thyroxine. However, evidence on the usefulness of thyroglobulin (Tg) to assess iodine status has not been extensively reviewed, particularly in pregnant women and adults.

SUMMARY

An electronic literature search was conducted using the Cochrane CENTRAL, Web of Science, PubMed, and Medline to locate relevant studies on Tg as a biomarker of iodine status. Since urinary iodine concentration (UIC) is the recommended method to assess iodine status in populations, only studies that clearly reported both Tg and UIC were included. For the purpose of this review, a median Tg <13 μg/L and a median UIC ≥100 μg/L (UIC ≥150 μg/L for pregnant women) were used to indicate adequate iodine status. We excluded studies conducted in subjects with either known thyroid disease or those with thyroglobulin antibodies. The search strategy and selection criteria yielded 34 articles of which nine were intervention studies. The majority of studies (six of eight) reported that iodine-deficient pregnant women had a median Tg ≥13 μg/L. However, large observational studies of pregnant women, including women with adequate and inadequate iodine status, as well as well-designed intervention trials that include both Tg and UIC, are needed. In adults, the results were equivocal because iodine-deficient adults were reported to have median Tg values of either <13 or ≥13 μg/L. Only studies in school-aged children showed that iodine-sufficient children typically had a median Tg <13 μg/L. Some of the inconsistent results may be partially explained by the use of different methodological assays and failure to assess assay accuracy using a certified reference material.

CONCLUSIONS

These data suggest that Tg does hold promise as a biomarker of iodine deficiency. However, it is associated with limitations. A median Tg cutoff of 13 μg/L warrants further investigation, particularly in adults or pregnant women, as there is a lack of both observational and intervention studies in these groups.

Long-term resistance trends of uropathogens and association with antimicrobial prophylaxis

BACKGROUND

The aim of this study was to identify long-term resistance trends of uropathogens and determine the effect of prophylaxis in a pediatric patient population.

MATERIALS AND METHODS

A total of 638 uropathogens were isolated from urine samples collected from children hospitalized for urinary tract infection during the 12-year study period (1997-2008) and analyzed.

RESULTS

The most frequent uropathogen identified was Escherichia coli (69 %), followed by Klebsiella spp. (9.7 %), Pseudomonas aeruginosa (6.7 %), Enterococcus spp. (5.6 %), and Proteus spp. (4.4 %). High resistance rates were observed for common agents used for empiric treatment, such as amoxicillin, cotrimoxazole, and ceftriaxone. Resistance increased over time for nitrofurantoin, ceftriaxone, and piperacilin-tazobactam (chi-square for trend p < 0.0002, p < 0.0034 and p < 0.014, respectively) and decreased for cefuroxime (p < 0.016) and gentamicin (p < 0.014). The use of prophylaxis was related to an increased proportion of non-E. coli pathogens (46.9 vs. 26.9 %; odds ratio 2.4, 95 % confidence interval 1.61-3.55; p < 0.0001), as well as to increased resistance of non-E. coli pathogens, and was a major risk factor associated with resistance to amoxiclav (p < 0.005), cotrimoxazole (p < 0.0001), cefuroxime (p < 0.0001), ceftriaxone (p < 0.0001), gentamicin (p < 0.0001), and nitrofurantoin (p < 0.0001).

CONCLUSIONS

Our findings point to considerable changes in the long-term resistance patterns of uropathogens and an association of prophylaxis with resistance. Our results suggest the need for continuous surveillance, re-evaluation of empiric regimens and further assessment of the role of prophylaxis in the treatment of urinary tract infection.

Detection of significant bacteriuria by use of the iQ200 automated urine microscope

In the microbiology laboratory, there is an augmented need for rapid screening methods for the detection of bacteria in urine samples, since about two-thirds of these samples will not yield any bacteria or will yield insignificant growth when cultured. Thus, a reliable screening method can free up laboratory resources and can speed up the reporting of a negative urine result. In this study, we have evaluated the detection of leukocytes, bacteria, and a new sediment indicator, the "all small particles" (ASP), by an automated instrument, the iQ200 urine analyzer, to detect negative urine samples that can be excluded from culture. A coupled automated strip reader (iChem Velocity), enabling the detection of nitrite and leukocyte esterase, was tested in parallel. In total, 963 urine samples were processed through both conventional urine culture and the iQ200/iChem Velocity workstation. Using the data, a multivariate regression model was established, and the predicted specificity and the possible reduction in urine cultures were calculated for the indicators and their respective combinations (leukocytes plus bacteria plus ASP and leukocyte esterase plus nitrite). Among all options, diagnostic performance was best using the whole microscopic content of the sample (leukocytes plus bacteria plus ASP). By using a cutoff value of ≥ 10(4) CFU/ml for defining a positive culture, a given sensitivity of 95% resulted in a specificity of 61% and a reduction in urine cultures of 35%. By considering the indicators alone, specificity and the culture savings were both much less satisfactory. The regression model was also used to determine possible cutoff values for running the instrument as part of daily routine. By using a graphical representation of all combinations possible, we derived cutoff values for leukocyte, bacterial, and ASP count, which should enable the iQ200 microscope to screen out approximately one-third of the urine samples, significantly reducing the workload in the microbiology laboratory.

Adenine phosphoribosyltransferase deficiency as a rare cause of renal allograft dysfunction

Adenine phosphoribosyltransferase deficiency is a rare autosomal recessive disorder manifesting as urolithiasis or crystalline nephropathy. It leads to the generation of large amounts of poorly soluble 2,8-dihydroxyadenine excreted in urine, yielding kidney injury and in some patients, kidney failure. Early recognition of the disease, institution of xanthine analog therapy to block the formation of 2,8-dihydroxyadenine, high fluid intake, and low purine diet prevent CKD. Because of symptom variability and lack of awareness, however, the diagnosis is sometimes extremely deferred. We describe a patient with adenine phosphoribosyltransferase deficiency who was diagnosed during evaluation of a poorly functioning second kidney allograft. This report highlights the risk of renal allograft loss in patients with undiagnosed adenine phosphoribosyltransferase deficiency and the need for improved early detection of this disease.

Quantitative determination of common urinary odorants and their glucuronide conjugates in human urine

Our previous study on the identification of common odorants and their conjugates in human urine demonstrated that this substance fraction is a little-understood but nonetheless a promising medium for analysis and diagnostics in this easily accessible physiological medium. Smell as an indicator for diseases, or volatile excretion in the course of dietary processes bares high potential for a series of physiological insights. Still, little is known today about the quantitative composition of odorous or volatile targets, as well as their non-volatile conjugates, both with regard to their common occurrence in urine of healthy subjects, as well as in that of individuals suffering from diseases or other physiological misbalancing. Accordingly, the aim of our study was to develop a highly sensitive and selective approach to determine the common quantitative composition of selected odorant markers in healthy human subjects, as well as their corresponding glucuronide conjugates. We used one- and two-dimensional high resolution gas chromatography-mass spectrometry in combination with stable isotope dilution assays to quantify commonly occurring and potent odorants in human urine. The studies were carried out on both native urine and on urine that had been treated by glucuronidase assays, with analysis of the liberated odor-active compounds using the same techniques. Analytical data are discussed with regard to their potential translation as future diagnostic tool.

The potential impact of biomarker-guided triage decisions for patients with urinary tract infections

OBJECTIVES

Current guidelines provide limited evidence as to which patients with urinary tract infection (UTI) require hospitalisation. We evaluated the currently used triage routine and tested whether a set of criteria including biomarkers like proadrenomedullin (proADM) and urea have the potential to improve triage decisions.

METHODS

Consecutive adults with UTI presenting to our emergency department (ED) were recruited and followed for 30 days. We defined three virtual triage algorithms, which included either guideline-based clinical criteria, optimised admission proADM or urea levels in addition to a set of clinical criteria. We compared actual treatment sites and observed adverse events based on the physician judgment with the proportion of patients assigned to treatment sites according to the three virtual algorithms. Adverse outcome was defined as transfer to the intensive care unit (ICU), death, recurrence of UTI or rehospitalisation for any reason.

RESULTS

We recruited 127 patients (age 61.8 ± 20.8 years; 73.2 % females) and analysed the data of 123 patients with a final diagnosis of UTI. Of these 123 patients, 27 (22.0 %) were treated as outpatients. Virtual triage based only on clinical signs would have treated only 22 (17.9 %) patients as outpatients, with higher proportions of outpatients equally in both biomarker groups (29.3 %; p = 0.02). There were no significant differences in adverse events between outpatients according to the clinical (4.5 %), proADM (2.8 %) or urea groups (2.8 %). The mean length of stay was 6.6 days, including 2.2 days after reaching medical stability.

CONCLUSIONS

Adding biomarkers to clinical criteria has the potential to improve risk-based triage without impairing safety. Current rates of admission and length of stay could be shortened in patients with UTI.

Can we interpret serum thyroglobulin results?

Thyroglobulin (Tg) is a tumour marker for differentiated thyroid cancer. Interpretation requires a knowledge of the current thyrotropin (TSH) concentration as secretion is TSH-dependent. While a raised serum Tg may be indicative of residual or recurrent thyroid cancer, trauma to the thyroid (e.g. surgical, biopsy or due to radioiodine treatment) also causes an increase. Tg may be measured when TSH is suppressed and also following recombinant TSH (rhTSH) stimulation. Interpretation of results in pregnancy and in children is discussed. Assay bias and interference by endogenous Tg antibodies (Abs) are the main confounders in the interpretation of results. Although there is an international standard for Tg, there are large differences in results and yet there are few assay-specific clinical decision limits. Patients should therefore be monitored with the same assay. Endogenous TgAbs may cause false-negative interference in immunometric assays and may cause false-positive results in radioimmunoassay. Although the measurement of TgAbs has been advocated for predicting interference, it is now clear that interference can still occur when TgAbs have not been detected, the effect being TgAb-assay-specific. Approaches to identifying those samples where there may be interference are discussed. The laboratory should have a protocol for the investigation of possible interferences and data on the bias of the Tg assay that they use. An appreciation of the clinical uses of the service is required as an understanding by endocrinologists, oncologists and endocrine surgeons of the analytical limitations of the service.

Renal carbonic anhydrases are involved in the reabsorption of endogenous nitrite

Nitrite (ONO(-)) exerts nitric oxide (NO)-related biological actions and its concentration in the circulation may be of particular importance. Nitrite is excreted in the urine. Hence, the kidney may play an important role in nitrite/NO homeostasis in the vasculature. We investigated a possible involvement of renal carbonic anhydrases (CAs) in endogenous nitrite reabsorption in the proximal tubule. The potent CA inhibitor acetazolamide was administered orally to six healthy volunteers (5 mg/kg) and nitrite was measured in spot urine samples before and after administration. Acetazolamide increased abruptly nitrite excretion in the urine, strongly suggesting that renal CAs are involved in nitrite reabsorption in healthy humans. Additional in vitro experiments support our hypothesis that nitrite reacts with CO(2), analogous to the reaction of peroxynitrite (ONOO(-)) with CO(2), to form acid-labile nitrito carbonate [ONOC(O)O(-)]. We assume that this reaction is catalyzed by CAs and that nitrito carbonate represents the nitrite form that is actively transported into the kidney. The significance of nitrite reabsorption in the kidney and the underlying mechanisms, notably a direct involvement of CAs in the reaction between nitrite and CO(2), remain to be elucidated.

Endocrine oncology in pregnancy

Endocrine tumours occur rarely in pregnant women but present clinicians with unique challenges. A high index of suspicion is often required to make a diagnosis since the symptoms and signs associated with many of these tumours, including insulinoma, adrenocortical carcinoma and phaeochromocytoma, mimic those of normal pregnancy or its complications, such as pre-eclampsia. The evidence base which informs management is very limited hence decisions on investigation and therapy must be individualised and undertaken jointly by the multidisciplinary medical team and the patient. The optimal strategy will depend on the nature and stage of the endocrine tumour, gestational stage, treatments available and patient wishes. Thus, surgical intervention, appropriately timed, may be considered in pregnancy for resectable adrenocortical carcinoma or phaeochromocytoma, but delayed until the postpartum period for well-differentiated thyroid cancer. Medical therapy may be required to reduce the drive to tumour growth, control symptoms of hormone excess and to minimise the risks of surgery, anaesthesia or labour.

Evaluation of Aution Max AX-4030 and 9UB Uriflet, 10PA Aution Sticks urine dipsticks in the automated urine test strip analysis

BACKGROUND

Aution Max AX-4030, a test strip analyzer recently introduced to the market, represents an upgrade of the Aution Max AX-4280 widely employed for urinalysis. This new instrument model can allocate two different test strips at the same time. In the present study the two instruments have been compared together with the usage of Uriflet 9UB and the recently produced Aution Sticks 10PA urine strips, the latter presenting an additional test area for the measurement of urinary creatinine.

METHODS

Imprecision and correlation between instruments and strips have been evaluated for chemical-physical parameters. Accuracy was evaluated for protein, glucose and creatinine by comparing the semi-quantitative results to those obtained by quantitative methods. The well-known interference effect of high ascorbic acid levels on urine glucose test strip determination was evaluated, ascorbic acid influence was also evaluated on protein and creatinine determination.

RESULTS

The two instruments have demonstrated comparable performances: precision and correlation between instruments and strips, evaluated for chemical-physical parameters, were always good. Furthermore, accuracy was always very good: results of protein and glucose semi-quantitative measurements resulted to be highly correlated with those obtained by quantitative methods. Moreover, the semi-quantitative measurements of creatinine, employing Aution Sticks 10PA urine strips, were highly comparable with quantitative results.

CONCLUSIONS

10PA urine strips are eligible for urine creatinine determination with the possibility of correcting urinalysis results for urinary creatinine concentration, whenever necessary and calculating the protein creatinine ratio. Further studies should be carried out to evaluate effectiveness and appropriateness of the usage of creatinine semi-quantitative analysis.

Preanalytical quality improvement: from dream to reality

Abstract Laboratory diagnostics (i.e., the total testing process) develops conventionally through a virtual loop, originally referred to as "the brain to brain cycle" by George Lundberg. Throughout this complex cycle, there is an inherent possibility that a mistake might occur. According to reliable data, preanalytical errors still account for nearly 60%-70% of all problems occurring in laboratory diagnostics, most of them attributable to mishandling procedures during collection, handling, preparing or storing the specimens. Although most of these would be "intercepted" before inappropriate reactions are taken, in nearly one fifth of the cases they can produce inappropriate investigations and unjustifiable increase in costs, while generating inappropriate clinical decisions and causing some unfortunate circumstances. Several steps have already been undertaken to increase awareness and establish a governance of this frequently overlooked aspect of the total testing process. Standardization and monitoring preanalytical variables is of foremost importance and is associated with the most efficient and well-organized laboratories, resulting in reduced operational costs and increased revenues. As such, this article is aimed at providing readers with significant updates on the total quality management of the preanalytical phase to endeavour further improvement for patient safety throughout this phase of the total testing process.

Evaluation of the Sysmex UF-1000i® urine flow cytometer in the diagnostic work-up of suspected urinary tract infection in a Dutch general hospital

BACKGROUND

Automation and standardization of sediment analysis of urine samples by flow cytometry might serve as an alternative to labor-intensive laboratory methods, such as microscopic examination and culture. The Sysmex UF-1000i is a urine flow cytometer that uses two separate channels for counting blood cells and bacteria.

METHODS

In this study, 358 urine samples were analyzed with the Sysmex UF-1000i in parallel with manual microscopy, Gram stain and bacterial culture, the latter considered the gold standard.

RESULTS

Reproducibility for detection of white and red blood cells and bacteria was good, while detection of yeast proved unreliable. Depending on the definition of urinary tract infection (UTI) used, the negative predictive value and the percentage of false-negative results were 100% and 0% [UTI ≥ 10(5) colony forming units (CFU)/mL] and 99% and 1.3%, (UTI ≥ 10(4) CFU/mL), respectively. Pre-screening with the Sysmex UF-1000i would have resulted in a reduction of bacterial culture by 42%. Carry over of bacteria between consecutive samples due to the use of fixed sample needle was observed, but did not result in false-positive interpretation of Sysmex UF-1000i results. Because of the occurrence of carry over, samples that have been analyzed with the Sysmex UF-1000i cannot be used for subsequent urine culture.

CONCLUSIONS

In conclusion, the Sysmex UF-1000i offers the possibility for screening high numbers of urine samples in a fast and standardized way, resulting in a reduction in workload and speeding the diagnostic process. It is not recommended for use in complicated patient populations, such as neutropenic patients and patients in whom yeast infection is suspected.

Validating the prediction of lower urinary tract infection in primary care: sensitivity and specificity of urinary dipsticks and clinical scores in women

BACKGROUND

Dipsticks are one of the most commonly used near-patient tests in primary care, but few clinical or dipstick algorithms have been rigorously developed.

AIM

To confirm whether previously documented clinical and dipstick variables and algorithms predict laboratory diagnosis of urinary tract infection (UTI).

DESIGN OF STUDY

Validation study.

SETTING

Primary care.

METHOD

A total of 434 adult females with suspected lower UTI had bacteriuria assessed using the European Urinalysis Guidelines.

RESULTS

Sixty-six per cent of patients had confirmed UTI. The predictive values of nitrite, leucocyte esterase (+ or greater), and blood (haemolysed trace or greater) were confirmed (independent multivariate odds ratios = 5.6, 3.5, and 2.1 respectively). The previously developed dipstick rule--based on presence of nitrite, or both leucocytes and blood-- was moderately sensitive (75%) but less specific (66%; positive predictive value [PPV] 81%, negative predictive value [NPV] 57%). Predictive values were improved by varying the cut-off point: NPV was 76% for all three dipstick results being negative; the PPV was 92% for having nitrite and either blood or leucocyte esterase. Urine offensive smell was not found to be predictive in this sample; for a clinical score using the remaining three predictive clinical features (urine cloudiness, dysuria, and nocturia), NPV was 67% for none of the features, and PPV was 82% for three features.

CONCLUSION

A clinical score is of limited value in increasing diagnostic precision. Dipstick results can modestly improve diagnostic precision but poorly rule out infection. Clinicians need strategies to take account of poor NPVs.

The pre-analytical challenges of routine urinalysis

An effective diagnostic strategy for urinalysis should be based on standard procedures for collection, transport, sample preparation and analysis. In view of a better reproducibility of the analyses, the pre-analytical requirements become stricter. Various sample methods can cause significant pre-analytical errors. It is a challenge for the laboratory to control the steps in the pre-analytical phase that contribute to pre-analytical variability. To reduce the variability, it is necessary to look at the pre-analytical process as a complete entity, from test ordering to the moment of specimen processing. Clinical laboratories are responsible for the clinical and financial outcome of this phase. In a culture of increasing productivity, lower costs and improving quality, the challenge is to use several tools designed to standardize and optimize urinalysis. Despite advances in the performance of analytic systems, the pre-analytical phase of modern urinalyses has not been studied very thoroughly. This review of the literature lights on different problems in current pre-analytical requirements for particle and test strip analysis of urine samples.

New generation IQ-200 automated urine microscopy analyzer compared with KOVA cell chamber

OBJECTIVE

The examination of the urine remains to be one of the most commonly performed tests in laboratory practice. Currently, laboratories also need to accredit their urine diagnostics by comparing their measurement methods to acceptable references. In this study we compared particle counts obtained by new generation automated technique, image capture analysis (IQ-200) with those of a standardized chamber counts.

DESIGN AND METHODS

The same 258 urine samples from different departments of a hospital assayed by IQ-200 were analyzed in parallel with the KOVA cell chamber system. Clinically significant discrepancy results (positive vs. negative) for red blood cell (RBC) and white blood cell (WBC) were also compared with those obtained by dipstick testing.

RESULTS

There was a good agreement between the automated system and sediment microscopy for RBCs, WBCs, and squamous epithelial cells (SCs) (r=0.90; r=0.80; r=0.72, respectively: P<0.001). The IQ-200 was more sensitive for determining RBCs, WBCs, and SCs than other formed elements.

CONCLUSIONS

IQ-200 can perform accurate quantification of microscopic element in urine. However, automated techniques are not completely free of error. Therefore, by adopting an appropriate algorithm and combining the results with stript analysis and other laboratory tests allows further reduction of clinically important errors.

Evaluation of the ARKRAY AUTION Eleven reflectometer in detecting microalbuminuria with AUTION Screen test strips and proteinuria with AUTION Sticks 10PA strips

OBJECTIVE

Albumin/creatinine and protein/creatinine ratios were measured with the ARKRAY AUTION Eleven reflectometer using AUTION Screen and AUTION Sticks 10PA strips, respectively, against quantitative Siemens Advia reference procedures from 368 patient urines, as an evaluation of their applicability for use in points-of-care and small laboratories.

MATERIAL AND METHODS

Direct reflectance measurements were utilized to estimate imprecision, as well as to suggest reclassification of ordinal scale categories into normoalbuminuria, microalbuminuria and macroalbuminuria groups (3.4 g/mol and 34 g/mol cut-off limits, corresponding to 30 mg/g and 300 mg/g creatinine in conventional units).

RESULTS

Analytically, ordinal scale albumin/creatinine ratios agreed in 86% of cases with those obtained from Advia measurements, resulting in a kappa coefficient of 0.79. Protein/creatinine ratios of the AUTION Sticks 10PA strip were classified into three groups at limits of 11.3 g/mol and 56.6 g/mol (100 mg/g and 500 mg/g in conventional units), with an agreement of 77% and a kappa coefficient of 0.65 against Advia procedures. To optimize clinical outcomes, cut-off reflectances of ordinal scale categories of AUTION Eleven were adjusted. The clinical specificity of detecting an increased albumin/creatinine ratio was then increased from 81% to 95%, with clinical sensitivity kept at 88% at the 3.4 g/mol limit of the reference procedure. Clinical specificity of the albuminuria field alone (at a clinical sensitivity of 88%) was only 73%. Adjustments to cut-off reflectances of the reported categories for protein/creatinine ratios increased clinical specificity from 54% to 94%, while losing clinical sensitivity from 97% to 89% only, with an improved concordance of 83% and a kappa coefficient of 0.75 against Advia measurements. The combination to creatinine measurements improved clinical specificity compared to 50% by the protein field alone. In economic terms, it is estimated that population screening for microalbuminuria using the AUTION Eleven reflectometer is cheaper than by quantitative albumin/creatinine measurements alone, based on the incidence of end-stage renal disease of 90 patients/million/year at the Northern Ostrobothnia Hospital District.

Benefits of the iQ200 automated urine microscopy analyser in routine urinalysis

BACKGROUND

Urine microscopic analysis is hampered by its lack in standardisation and semi-quantitative reports, resulting in limited reliability. Automation of urinalysis could overcome these problems.

METHODS

We compared the performance of the iQ200 with traditional microscopy and strip analysis in routine urinalysis. A total of 1482 routine samples, positive in dipstick testing, were evaluated for erythrocytes, leukocytes, casts, dysmorphic erythrocytes and bacteria using the iQ200 and traditional microscopy. The results of 320 of these samples were linked to underlying urological pathology as well as results from bacterial culturing.

RESULTS

Analytically, the iQ200 surpasses traditional microscopy. The identification of casts and dysmorphic erythrocytes in routine samples improves when using the iQ200, although the sub-classification of casts required well-trained technicians. The auto-classification of particles was least reliable for yeast and bacterial cocci. The quantitative reports, and therefore the use of precise cut-off points allowed earlier and improved detection of urinary tract pathology.

CONCLUSIONS

The performance of the iQ200 is equal to traditional microscopy, but it strongly improves the reliability of urinalysis by standardisation, quantitative reports and improved workflow. From a clinical point of view, renewed attention and improvement of routine urinalysis aids in the efficient detection of renal and urinary tract pathology.

Optimizing the diagnostic work-up of acute uncomplicated urinary tract infections

BACKGROUND

Most diagnostic tests for acute uncomplicated urinary tract infections (UTIs) have been previously studied in so-called single-test evaluations. In practice, however, clinicians use more than one test in the diagnostic work-up. Since test results carry overlapping information, results from single-test studies may be confounded. The primary objective of the Amsterdam Cystitis/Urinary Tract Infection Study (ACUTIS) is to determine the (additional) diagnostic value of relevant tests from patient history and laboratory investigations, taking into account their mutual dependencies. Consequently, after suitable validation, an easy to use, multivariable diagnostic rule (clinical index) will be derived.

METHODS

Women who contact their GP with painful and/or frequent micturition undergo a series of possibly relevant tests, consisting of patient history questions and laboratory investigations. Using urine culture as the reference standard, two multivariable models (diagnostic indices) will be generated: a model which assumes that patients attend the GP surgery and a model based on telephone contact only. Models will be made more robust using the bootstrap. Discrimination will be visualized in high resolution histograms of the posterior UTI probabilities and summarized as 5th, 10th, 25th 50th, 75th, 90th, and 95th centiles of these, Brier score and the area under the receiver operating characteristics curve (ROC) with 95% confidence intervals. Using the regression coefficients of the independent diagnostic indicators, a diagnostic rule will be derived, consisting of an efficient set of tests and their diagnostic values. The course of the presenting complaints is studied using 7-day patient diaries. To learn more about the natural history of UTIs, patients will be offered the opportunity to postpone the use of antibiotics.

DISCUSSION

We expect that our diagnostic rule will allow efficient diagnosis of UTIs, necessitating the collection of diagnostic indicators with proven added value. GPs may use the rule (preferably after suitable validation) to estimate UTI probabilities for women with different combinations of test results. Finally, in a subcohort, an attempt is made to identify which indicators (including antibiotic treatment) are useful to prognosticate recovery from painful and/or frequent micturition.