Age-and sex-specific reference intervals of total cholesterol, LDL cholesterol, HDL cholesterol and non-HDL cholesterol. Comparison of two algorithms for the indirect estimation of reference intervals

Objectives

Reference intervals of total cholesterol concentrations in plasma and of their fractions low-density lipoprotein (LDL)-, high-density lipoprotein (HDL)-and non-HDL concentrations are seldom studied with respect to the relevance of age and sex. Therefore, the effect of age and sex on the reference intervals was reinvestigated with 2 indirect procedures.

Methods

As an indirect approach, the truncated minimum chi-square method was applied. All analyses were performed by computer programs available. The script published on the homepage of the German Society of Clinical Chemistry and Laboratory Medicine (DGKL) allows to derive a continuous age dependency of reference intervals together with their confidence and equivalence limits. The results of this approach were compared with those obtained by an indirect method developed more recently, the refineR algorithm.

Results

In the present study, the upper reference limits of total cholesterol varied from 5.1 to 7.8 mmol/L (197–302 mg/dL) depending on various biological variables (as age, sex, inpatients versus outpatients). These upper limits increased with age. Differences between sexes can be neglected except for the age above 80 years. The pattern of reference limits of LDL cholesterol and non-HDL cholesterol paralleled those of total cholesterol. The reference limits of HDL cholesterol were higher in women than in men but were independent of age.

Conclusions

Reference limits for the concentrations of total cholesterol and their fractions LDL-, HDL-and non-HDL concentrations should be stratified for age and sex.

The prevalence of Mycoplasma genitalium (MG) and Trichomonas vaginalis (TV) at testing centers in Belgium, Germany, Spain, and the UK using the cobas TV/MG molecular assay

Mycoplasma genitalium (MG) and Trichomonas vaginalis (TV) can lead to long-term sequelae in males and females; however, global prevalence data vary between geographical regions, as these sexually transmitted infections are not included in routine screening. The objective of this study was to use the cobas^® TV/MG assay to assess the point prevalence of TV and MG in specimens from men and women over a broad European geographical area. Urine, vaginal, endocervical, and rectal samples were collected from patients aged ≥ 18 years receiving Chlamydia trachomatis (CT) and/or Neisseria gonorrhoeae (NG) screening as per local standard of care at sites in Belgium, Germany, Spain, and the UK (Wales). Remnant samples were assessed using the cobas TV/MG assay. Analysis of 2795 samples showed that MG prevalence varied slightly across female sample types (range: 1.7-5.8%; p = 0.0042). MG prevalence was higher in male rectal samples (12.5%) than in male urine samples (3.9%; p < 0.0001). TV prevalence was low in male (0.8%; 12/1535) and female (1.3%; 16/1260) samples across all sites. Co-infection of TV/MG with CT or NG was 10.0% (19/190) and 9.6% (7/73), respectively, in both male and female samples. MG and TV prevalence rates were comparable to the published literature in Europe. MG prevalence was highest in male rectal samples; as rectal testing is an off-label use of the cobas TV/MG assay, the clinical utility of this assay for rectal testing should be further investigated.

High-resolution pediatric reference intervals for 15 biochemical analytes described using fractional polynomials

OBJECTIVES

Assessment of children's laboratory test results requires consideration of the extensive changes that occur during physiological development and result in pronounced sex- and age-specific dynamics in many biochemical analytes. Pediatric reference intervals have to account for these dynamics, but ethical and practical challenges limit the availability of appropriate pediatric reference intervals that cover children from birth to adulthood. We have therefore initiated the multi-center data-driven PEDREF project (Next-Generation Pediatric Reference Intervals) to create pediatric reference intervals using data from laboratory information systems.

METHODS

We analyzed laboratory test results from 638,683 patients (217,883-982,548 samples per analyte, a median of 603,745 test results per analyte, and 10,298,067 test results in total) performed during patient care in 13 German centers. Test results from children with repeat measurements were discarded, and we estimated the distribution of physiological test results using a validated statistical approach (kosmic).

RESULTS

We report continuous pediatric reference intervals and percentile charts for alanine transaminase, aspartate transaminase, lactate dehydrogenase, alkaline phosphatase, γ-glutamyl-transferase, total protein, albumin, creatinine, urea, sodium, potassium, calcium, chloride, anorganic phosphate, and magnesium. Reference intervals are provided as tables and fractional polynomial functions (i.e., mathematical equations) that can be integrated into laboratory information systems. Additionally, Z-scores and percentiles enable the normalization of test results by age and sex to facilitate their interpretation across age groups.

CONCLUSIONS

The provided reference intervals and percentile charts enable precise assessment of laboratory test results in children from birth to adulthood. Our findings highlight the pronounced dynamics in many biochemical analytes in neonates, which require particular consideration in reference intervals to support clinical decision making most effectively.

Age and sex dependent reference intervals for random plasma/serum glucose concentrations related to different sampling devices and determined by an indirect procedure with data mining

The glucose concentration in plasma or serum is one of the most often requested analytical values in laboratory medicine. Whereas the analytical part of the glucose determination is well standardised, the standardisation of the pre-examination part (pre-analytical phase) is not sufficiently solved, yet. In view of the present controversial discussion regarding the most efficient prevention of pre-analytical glycolysis, the question arises whether the economical and logistic expenses for inhibiting glycolysis determining random glucose concentration are justified. In hospitals with adequate logistics (e.g. pneumatic tube systems for blood tubes) to guarantee a blood sample transport time of about 1 – 2 h, plasma or serum without prevention of glycolysis can be applied for random glucose concentrations if the reference limits are estimated by the laboratory. If such logistics are not available, especially in primary care services, either plasma or serum samples or whole blood in special tubes with anti-glycolytic additives may be sent to the laboratory.

Next-generation reference intervals for pediatric hematology

Background Interpreting hematology analytes in children is challenging due to the extensive changes in hematopoiesis that accompany physiological development and lead to pronounced sex- and age-specific dynamics. Continuous percentile charts from birth to adulthood allow accurate consideration of these dynamics. However, the ethical and practical challenges unique to pediatric reference intervals have restricted the creation of such percentile charts, and limitations in current approaches to laboratory test result displays restrict their use when guiding clinical decisions. Methods We employed an improved data-driven approach to create percentile charts from laboratory data collected during patient care in 10 German centers (9,576,910 samples from 358,292 patients, 412,905-1,278,987 samples per analyte). We demonstrate visualization of hematology test results using percentile charts and z-scores (www.pedref.org/hematology) and assess the potential of percentiles and z-scores to support diagnosis of different hematological diseases. Results We created percentile charts for hemoglobin, hematocrit, red cell indices, red cell count, red cell distribution width, white cell count and platelet count in girls and boys from birth to 18 years of age. Comparison of pediatricians evaluating complex clinical scenarios using percentile charts versus conventional/tabular representations shows that percentile charts can enhance physician assessment in selected example cases. Age-specific percentiles and z-scores, compared with absolute test results, improve the identification of children with blood count abnormalities and the discrimination between different hematological diseases. Conclusions The provided reference intervals enable precise assessment of pediatric hematology test results. Representation of test results using percentiles and z-scores facilitates their interpretation and demonstrates the potential of digital approaches to improve clinical decision-making.

Saisonale und überregionale Unterschiede der Selenversorgung bei Pferden

Gegenstand und Ziel: Überprüfung der Selenversorgung von Pferden in verschiedenen Ländern Europas. Material und Methoden: In Serumproben von 137152 Pferden aus Europa, die im Zeitraum vom 1.1.2006 bis 31.12.2011 von Tierärzten in das IDEXX Vet Med Labor nach Ludwigsburg eingesandt wurden, erfolgte eine routinemäßige Bestimmung der Selenkonzentration mittels ICP-Analytik. Ergebnisse: Die Selengehalte im Boden scheinen für die Selenversorgung zentrale Bedeutung zu besitzen. In Ländern, die in Ozeannähe liegen, besteht durch den Seleneintrag eine bessere Selenversorgung der Pferdepopulation als in zentraleuropäischen Ländern. Dänemark und die Niederlande stehen in der Selenversorgung an erster Stelle. Die schlechteste Selenversorgung in Europa zeigen die Länder Österreich und Luxemburg. In fast allen Ländern lassen sich große regionale Unterschiede nachweisen. Besonders in Deutschland besteht vor allem ein West-Ost-Gefälle in der Selenversorgung. Das Nord-Süd-Gefälle ist weniger ausgeprägt, wie die Selengehalte im Boden zeigen. Eine sehr schlechte Selenversorgung findet sich in den Zentralgebieten Österreichs mit einer Unterversorgung von über 50%. Schlussfolgerung und klinische Relevanz: Die individuelle Pferdehaltung und -versorgung spielt für die Selenversorgung eine große Rolle. Da die Selenkonzentration in der Grundfutterration sehr stark schwankt und Spurenelementanalysen des Grundfutters meist nicht durchgeführt werden, gestaltet sich die Anpassung der Mineralfuttergabe für Selen oft sehr schwierig. Daher wird eine jährliche Kontrolle des Selengehalts im Serum empfohlen. Bei Pferden mit niedrigen Selenwerten kann die Unterversorgung durch Gaben von selenhaltigem Zusatz-/Mineralfutter behoben werden.

Saisonale und überregionale Unterschiede im Selenversorgungsstatus von Rindern

Gegenstand und Ziel: Überprüfung des Selenversorgungsstatus von Rindern in verschiedenen Ländern Europas. Material und Methode: In 35 722 Serumproben von Rindern aus Europa mit unbekannter klinischer Symptomatik, die im Zeitraum vom 1.1.2006 bis 30.06.2013 von Tierärzten in das IDEXX Vet Med Labor nach Ludwigsburg eingesandt wurden, erfolgte eine routinemäßige Bestimmung der Selenkonzentration mittels ICP-Analytik. Ergebnisse: Die Selenversorgung bei Rindern zeigt saisonale Unterschiede mit hohen Serumkonzentrationen im Winter und niedrigen Serumgehalten im Sommer sowie einen generellen Trend zur Verschlechterung der Selenversorgung über die letzten Jahre. Die Betriebsgröße, die Haltungsform, die allgemeine wirtschaftliche Lage und der Selengehalt im Boden sowie die länderspezifische Fütterung scheinen für die Selenversorgung von zentraler Bedeutung zu sein. Ungarn und die skandinavischen Länder Schweden und Dänemark sind in der Selenversorgung weit führend. Die schlechteste Versorgungslage besteht in Frankreich und Luxemburg (> 50%) der beprobten Rinder im unterversorgten Bereich). Schlussfolgerung und klinische Relevanz: Eine optimale Selenversorgung ist im Rinderbereich sehr wichtig, da durch Mangelerscheinungen gesundheitliche Probleme und Leistungsbeeinträchtigungen (Milchleistung) entstehen. Die Selenkonzentration schwankt je nach Fütterungsart und Haltungsbedingungen sehr stark, sodass eine jährliche Kontrolle der Selenversorgung in den Herden empfohlen wird.

High-Throughput Testing of Urogenital and Extragenital Specimens for Detection of Chlamydia Trachomatis and Neisseria Gonorrhoeae with Cobas® CT/NG

We compared the analytical and clinical performance of cobas^® CT/NG for use on the Cobas^® 6800/8800 Systems with the Cobas^® 4800 CT/NG Test from urogenital and extragenital specimens in over 12,000 specimens from both male and female subjects in Germany and the United States. The analytical sensitivity was ≤40 EB/ml for Chlamydia trachomatis (CT) and ≤1 CFU/ml for Neisseria gonorrhoeae (NG). Using clinical specimens, the overall percent agreement with the Cobas^® 4800 CT/NG Test was >98.5%. Across urogenital specimens, there were 93 discrepant specimens; 76 (93.8%) of 81 CT discrepant specimens were 6800+/4800– and 10 (83.3%) of 12 NG discrepant specimens were 6800+/4800–. Sequencing verified CT results for 45 (61.6%) of 73 samples positive by 6800 and 1 (20%) of 5 positive by 4800. Similarly, 7 (70.0%) of 10 NG samples positive by 6800 and 1 of 2 positive by 4800 were confirmed by sequencing. Among discrepant extragenital specimens (all 6800+/4800–), 7 (50%) of 14 oropharyngeal and 23 (76.7%) of 30 anorectal CT discordant samples were confirmed as CT positive by sequencing; all 8 anorectal and 20 (90.9%) of 22 oropharyngeal NG discordant results were also confirmed as NG positive. In conclusion, Cobas^® CT/NG for use on the Cobas^® 6800/8800 Systems provides high-throughput automated solutions for sexually transmitted infection (STI) screening programs.

Occurrence and molecular typing of Giardia isolates in pet rabbits, chinchillas, guinea pigs and ferrets collected in Europe during 2006-2012

A total of 1180 faecal samples (528 from rabbits, 531 from chinchillas and 121 from guinea pigs) collected during 2006-2012 by veterinarians in Germany and in other European countries were submitted to a diagnostic laboratory for Giardia testing by means of coproantigen ELISA. Of these samples, 40 rabbits (7.6 per cent), 326 chinchillas (61.4 per cent) and five guinea pigs (4.1 per cent ) were found to be positive. To gain insights into the genetic identity of Giardia in small mammals, ELISA-positive samples from 23 chinchillas, five ferrets, a rabbit, and a Desmarest's hutia were investigated by PCR and sequencing of fragments of the small subunit ribosomal DNA (ssu), the triose phosphate isomerase (tpi) and the β-giardin (bg) genes. At the ssu locus, assemblage B was identified in 28 of 30 isolates, whereas assemblage A and D were each detected in one sample. The majority of isolates from chinchillas and those from ferrets had Giardia duodenalis sequences identical to sub-assemblages AI or BIV, based on either a single locus (tpi or bg) or multiple loci (tpi and bg). As sub-assemblages AI or BIV are associated with human infection, these results indicate that small mammals can act as reservoirs of cysts potentially infectious to humans.

Lemierre's syndrome: a serious complication of a routine dental procedure

Lemierre's syndrome is the clinical presentation characterized by oropharyngeal or tonsillar infection, anaerobic septicaemia often with distant septic emboli, and clinical or radiological evidence of thrombosis of the internal jugular vein. We report a case of Lemierre's syndrome in a 44-year-old type II diabetic male. This case is unique for two reasons. Firstly, we believe it is the first reported iatrogenic case following a routine dental procedure. Secondly, the internal jugular vein thrombosis was found to occur on the contralateral side to the primary infection.

[Differences in the selenium supply of cattle across Europe]

OBJECTIVE

Evaluation of differences in the selenium supply of cattle across Europe.

MATERIAL AND METHODS

A total of 35,722 serum samples from cattle throughout Europe (unknown clinical status), which had been sent by veterinarians to the IDEXX Vet Med Lab Ludwigsburg, Germany between January 1st, 2006, and June 30th, 2013, were analyzed routinely for the selenium concentration using ICP-analysis.

RESULTS

The collective data of the selenium concentration in cattle serum display seasonal variations, with a lower concentration during summer when compared to the winter. In recent years, the selenium supply has decreased. The farm size, husbandry conditions, economic situation, soil selenium concentration and the countries' specific feeding together play a key role in the selenium supply of the herd. Hungary and the Scandinavian countries Sweden and Denmark show the best selenium supply in Europe. A very poor situation exists in France and Luxembourg (> 50% of the cattle samples are undersupplied).

CONCLUSION AND CLINICAL RELEVANCE

An optimal selenium supply for cattle is very important; a trace element deficiency can cause negative health effects and impair herd performance. The selenium concentration varies considerably, depending upon feeding and husbandry conditions. Therefore, a serum selenium analysis in cattle is essential and should be performed annually.

Myoepithelial cell differentiation markers in prepubertal bovine mammary gland: effect of ovariectomy

We reported previously that ovariectomy alters prepubertal development of mammary myoepithelial cells (MC) by mechanisms that are not well understood. Therefore, in the present study, we analyzed expression of 2 myoepithelial differentiation markers, α-smooth muscle actin (SMA) and the common acute lymphoblastic leukemia antigen (CD10), in mammary parenchymal tissue from intact (INT) and ovariectomized (OVX) heifers. On d 40, Holstein heifers underwent either an ovariectomy (OVX; n=16) or a sham (INT; n=21) operation. At 55, 70, 85, 100, 130, and 160 d of age, tissues were collected, and multispectral imaging was used to quantify immunofluorescent staining for myoepithelial cell (MC) markers. Fluorescent intensity (FI) of the markers was normalized against a control sample. In the basal epithelial layer, CD10 FI was less and SMA FI was greater in OVX than INT. The ratio of SMA to CD10 FI, as a proxy indicator for MC differentiation, was greater in tissue from OVX compared with INT heifers after 55 d of age. The staining for SMA was frequently more intense along the basal aspect of cells, whereas CD10 expression was localized on the apical surface of the MC. In mammary tissue from both INT and OVX heifers, we observed basal cells that were negative for both CD10 and SMA, some of which appeared to span the distance from basement membrane to the ductal lumen. Interestingly, we also observed CD10+ cells adjacent to the ductal lumen, a situation that was more prevalent in OVX than in INT heifers. Also, ovariectomy affects MC expression of both SMA and CD10, as well as the pattern of MC development. Myoepithelial cells are known to limit parenchymal growth in other species. Involvement of MC as regulators of prepubertal bovine mammary development is worthy of further investigation.

[Seasonal and national differences in the selenium supply of horses across Europe]

OBJECTIVE

Evaluation of the differences in the selenium supply to horses across Europe.

MATERIAL AND METHODS

Serum samples from 137,152 horses all over Europe, which had been sent by veterinarians to IDEXX Vet Med Labor between January 1st 2006 and December 31st 2011, were routinely analyzed for the selenium concentration by means of ICP-analytic.

RESULTS

The selenium content of the soil appears to play a key role in the selenium supply to horses. Countries closer to the ocean provided a better selenium supply than countries in central Europe. The best selenium supply can be seen in Denmark and in the Netherlands. The lowest values are obtained from Austria and Luxembourg. Furthermore, very large differences exist in the selenium supply in different regional areas within a country. This is particularly obvious across the German federal states, with a very good supply in the western areas and a very poor supply in the eastern states. The north-south divide is less obvious, similar to the selenium content of the soil. A very poor situation exists for central Austria, where more than 50% of the equine samples revealed an undersupply.

CONCLUSION AND CLINICAL RELEVANCE

Individual horse-keeping and feeding represent key points in the selenium supply. Because of the differences in the selenium concentrations in pasture, silage and hay, and due to the lack of routinely performed analysis of the mineral content of food, it is extremely difficult from a management point of view to precisely adapt the intake of minerals. Hence, serum analyses of selenium in horses are very important and should be performed annually. In the case of an undersupply, selenium has to be supplemented with mineral food.

Vitamin and calcium supplement use is associated with decreased adenoma recurrence in patients with a previous history of neoplasia

INTRODUCTION

Although some have suggested that certain vitamins or calcium supplements may reduce adenoma recurrence, our own prior retrospective study found no such effects. The purpose of this case-control study was to further investigate whether regular vitamin or calcium supplement intake influenced the incidence of recurrent adenomatous polyps in patients with previous neoplasia who were undergoing follow-up colonoscopy.

METHODS

This study enrolled 1,162 patients who underwent colonoscopy by one of three surgeons at Columbia-Presbyterian Medical Center in New York City between March 1993 and February 1997. Of these patients 448 (250 males) had a previous diagnosis of colorectal neoplasia (cancer, adenomas, or dysplasia). Of these, 183 (40.8 percent) had an adenoma at the index colonoscopy. Information was collected on personal and family history of colonic diseases, cigarette smoking, medication, and vitamin and micronutrient supplement usage on a questionnaire that was completed by the patients before the colonoscopy. Odds ratios were obtained by unconditional logistic regression analysis, adjusting for age and gender, and used adenoma recurrence at index colonoscopy as the outcome.

RESULTS

The mean interval between colonoscopic examinations was 37 months for the recurrent adenoma group and 38 months for the nonrecurrent group of patients (P = not significant). In this case-control study we found a protective effect for the use of vitamin supplements in general (any vitamin) on the recurrence of adenomas (odds ratio, 0.41; 95 percent confidence interval, 0.27-0.61). Specifically, this protective effect was observed for the use of multivitamins (odds ratio, 0.47; 95 percent confidence interval, 0.31-0.72), vitamin E (odds ratio, 0.62; 95 percent confidence interval, 0.39-0.98), and for calcium supplementation (odds ratio, 0.51; 95 percent confidence interval, 0.27-0.96). Nonsignificant protective effects were noted for carotene/vitamin A, vitamin D, and vitamin C.

CONCLUSIONS

The use of multivitamins, vitamin E, and calcium supplements were found to be associated with a lower incidence of recurrent adenomas in a population of patients with history of previous colonic neoplasia. Prospective, randomized trials are needed to better assess the impact of these agents and to determine whether the use of these supplements is associated with a protective effect against recurrent adenomas.

Removal of dermal edema with class I and II compression stockings in patients with lipodermatosclerosis

BACKGROUND

Lipodermatosclerosis is a sequela of deep venous insufficiency and a risk factor for the occurrence of venous leg ulceration. Medical compression stockings facilitate leg ulcer healing and prevent occurrence of ulcers resulting from removal of edema. Although the exact level of compression necessary for removal of dermal edema in patients with deep venous insufficiency has not been established, garments providing high compressive values of 30 to 40 mm Hg have been recommended. Dermal edema can be visualized by high-frequency ultrasonography.

OBJECTIVE

We used ultrasound imaging to study whether a lower level of compression (class I 18 to 26 mm Hg vs class II 26 to 36 mm Hg) is effective in removal of dermal edema. This question is important because the use of hosiery with a lower compression class would enhance compliance and enable treatment of patients with mixed arteriovenous disease.

METHODS

In 11 patients skin images were obtained with 20 MHz ultrasound from the malleolar region in lipodermatosclerotic skin and corresponding normal skin of the contralateral leg. The ratio of low echogenic pixel number to total pixel number (LEP/TP), which correlates with dermal water, was measured before and after 5 days of applied compression in two treatment courses where classes of compression were switched randomly. Ankle circumference was also measured.

RESULTS

We found that LEP/TP was 33% higher in lipodermatosclerotic skin than in the matched normal skin indicating presence of skin edema. Application of class I and II compressive hosiery resulted in LEP/TP decrease by 17% (95% confidence interval, 0.07 to 0.26) and 14% (95% confidence interval, 0.04 to 0.21), respectively, suggestive of dermal edema reduction. No statistically significant difference in efficacy of dermal edema removal between class I and II was found. No changes in ankle circumference after application of both classes of compression was observed.

CONCLUSION

Application of light and moderate compression results in a partial edema removal from the dermis in lipodermatosclerosis in the absence of measurable reduction in leg circumference. Class I compression is as effective as class II for elimination of dermal edema. These data indicate that light compression may be a useful modality for patients with deep venous insufficiency and lipodermatosclerosis who are not eligible for treatment with garments having higher compressive forces.

The effect of calcium and vitamin supplements on the incidence and recurrence of colorectal adenomatous polyps

BACKGROUND

Recent attention has focused on calcium and certain vitamins as potential protective agents against colorectal neoplasia.

METHODS

Two case-control studies were conducted on patients who underwent colonoscopy between 1986 and 1988, comparing 297 patients with newly diagnosed adenomas with 505 controls (without current or prior history of neoplasia), and 198 patients with recurrent adenomas with 347 recurrent controls (with no current neoplasia, but with a history of polypectomy). Subjects were interviewed regarding their regular usage of supplementation with vitamins A, C, D, and E, or with calcium, multivitamins, or any vitamin supplements.

RESULTS

No consistent associations were observed with the use of any of these supplements.

CONCLUSIONS

More studies are necessary to confirm these findings. It may be necessary to develop other chemopreventive agents, such as aspirin, for colorectal neoplasia.