Haematological reference intervals for pregnant Icelandic mares on pasture

BACKGROUND

Few studies have been conducted on haematological reference intervals (RIs) in Icelandic horses. Reference intervals have been published for Icelandic horses in Austria and a preliminary study in Iceland compared haematological values in riding horses to published RIs for other breeds as well as Icelandic horses abroad. Haematological parameters can vary greatly due to factors such as breed, gender, age, reproductive status, and training, as well as feeding, prior exercise and management method. Icelandic broodmares are kept on pasture under supervision throughout the year, with haylage provided during the winter, and it is therefore of interest to establish haematological reference intervals for pregnant broodmares in Iceland. The purpose of this study was to establish haematological RIs specific to Icelandic broodmares in the first months of pregnancy, kept on pasture. Blood samples from 183 mares, stabilised in EDTA were analysed using IDEXX ProCyte Dx and total protein was analysed in serum samples from 157 of the 183 mares, using IDEXX Catalyst One analyser. The RIs were established using the guidelines of the American Society for Veterinary Clinical Pathology.

RESULTS

The RIs for red blood cell count, haematocrit and haemoglobin were higher in pasture-kept Icelandic mares in early pregnancy, most of which were lactating, than in pregnant mares of other breeds. This was also true for white blood cell count, as well as numbers of monocytes, eosinophils, and basophils, which in some instances might illustrate problems in the automated categorisation of some leukocytes.

CONCLUSIONS

As no RIs have been published for other pasture-kept Icelandic horses, future investigations should include other groups of pasture-kept Icelandic horses. Such an analysis might elucidate the effect of breed, management, and pregnancy on haematological values in pasture-kept Icelandic horses.

Assessing accuracy of genotype imputation in the Afrikaner and Brahman cattle breeds of South Africa

Imputation may be used to rescue genomic data from animals that would otherwise be eliminated due to a lower than desired call rate. The aim of this study was to compare the accuracy of genotype imputation for Afrikaner, Brahman, and Brangus cattle of South Africa using within- and multiple-breed reference populations. A total of 373, 309, and 101 Afrikaner, Brahman, and Brangus cattle, respectively, were genotyped using the GeneSeek Genomic Profiler 150 K panel that contained 141,746 markers. Markers with MAF ≤ 0.02 and call rates ≤ 0.95 or that deviated from Hardy Weinberg Equilibrium frequency with a probability of ≤ 0.0001 were excluded from the data as were animals with a call rate ≤ 0.90. The remaining data included 99,086 SNPs and 360 Afrikaner, 75,291 SNPs and 288 animals Brahman, and 97,897 SNPs and 99 Brangus animals. A total of 7986, 7002, and 7000 SNP from 50 Afrikaner and Brahman and 30 Brangus cattle, respectively, were masked and then imputed using BEAGLE v3 and FImpute v2. The within-breed imputation yielded accuracies ranging from 89.9 to 96.6% for the three breeds. The multiple-breed imputation yielded corresponding accuracies from 69.21 to 88.35%. The results showed that population homogeneity and numerical representation for within and across breed strategies, respectively, are crucial components for improving imputation accuracies.

Evaluation of 99th percentile and reference change values of a high-sensitivity cTnI method: A multicenter study

BACKGROUND

The Italian Society of Clinical Biochemistry (SIBioC) and the Italian Section of the European Ligand Assay Society (ELAS) have recently promoted a multicenter study (Italian hs-cTnI Study) with the aim to accurately evaluate analytical performances and reference values of the most popular cTnI methods commercially available in Italy. The aim of this article is to report the results of the Italian hs-cTnI Study concerning the evaluation of the 99th percentile URL and reference change (RCV) values around the 99th URL of the Access cTnI method.

MATERIALS AND METHODS

Heparinized plasma samples were collected from 1306 healthy adult volunteers by 8 Italian clinical centers. Every center collected from 50 to 150 plasma samples from healthy adult subjects. All volunteers denied the presence of chronic or acute diseases and had normal values of routine laboratory tests (including creatinine, electrolytes, glucose and blood counts). An older cohort of 457 adult subjects (mean age 63.0 years; SD 8.1 years, minimum 47 years, maximum 86 years) underwent also ECG and cardiac imaging analysis in order to exclude the presence of asymptomatic cardiac disease.

RESULTS AND CONCLUSIONS

The results of the present study confirm that the Access hsTnI method using the DxI platform satisfies the two criteria required by international guidelines for high-sensitivity methods for cTn assay. Furthermore, the results of this study confirm that the calculation of the 99th percentile URL values are greatly affected not only by age and sex of the reference population, but also by the statistical approach used for calculation of cTnI distribution parameters.

Evaluation of analytical performance of immunoassay methods for cTnI and cTnT: From theory to practice

Current guidelines worldwide recommend cardiac troponins I (cTnI) and T (cTnT) as the biomarkers of choice for the differential diagnosis of acute coronary syndrome (ACS), and the measurement of the 99th upper reference population limit (URL) value for cardiac troponins, with an imprecision of ≤10 CV%. Measuring the 99th URL of cTnI and cTnT is a challenging analytical task due to low biomarker concentrations present in healthy subjects. Therefore, since the year 2006, several manufacturers have established new generation cTnI and cTnT immunoassays with an improved analytical sensitivity in accordance with the quality specifications described in international guidelines, the more recent of which state that only immunoassays that meet the required quality specifications should be considered "high-sensitivity" methods. For the early diagnosis of ACS, and for the stratification of cardiovascular risk in cardiac patients and the general population, high-sensitivity methods should be employed. It is therefore important for laboratory professionals and clinicians to gain a thorough understanding of the analytical performances of immunoassay methods for cTnI and cTnT, especially at low to normal concentration ranges. The aim of the present study was to analyze critical aspects related to definition, analytical performance, pathophysiological interpretations, and the clinical relevance of high-sensitivity cardiac troponin assays.

Developmental and internal validation of a novel 13 loci STR multiplex method for Cannabis sativa DNA profiling

Marijuana (Cannabis sativa L.) is a plant cultivated and trafficked worldwide as a source of fiber (hemp), medicine, and intoxicant. The development of a validated method using molecular techniques such as short tandem repeats (STRs) could serve as an intelligence tool to link multiple cases by means of genetic individualization or association of cannabis samples. For this purpose, a 13 loci STR multiplex method was developed, optimized, and validated according to relevant ISFG and SWGDAM guidelines. The STR multiplex consists of 13 previously described C. sativa STR loci: ANUCS501, 9269, 4910, 5159, ANUCS305, 9043, B05, 1528, 3735, CS1, D02, C11, and H06. A sequenced allelic ladder consisting of 56 alleles was designed to accurately genotype 101 C. sativa samples from three seizures provided by a U.S. Customs and Border Protection crime lab. Using an optimal range of DNA (0.5-1.0ng), validation studies revealed well-balanced electropherograms (inter-locus balance range: 0.500-1.296), relatively balanced heterozygous peaks (mean peak height ratio of 0.83 across all loci) with minimal artifacts and stutter ratio (mean stutter of 0.021 across all loci). This multi-locus system is relatively sensitive (0.13ng of template DNA) with a combined power of discrimination of 1 in 55 million. The 13 STR panel was found to be species specific for C. sativa; however, non-specific peaks were produced with Humulus lupulus. The results of this research demonstrate the robustness and applicability of this 13 loci STR system for forensic DNA profiling of marijuana samples.

Laboratory diagnosis of gestational diabetes: An in silico investigation into the effects of pre-analytical processing on the diagnostic sensitivity and specificity of the oral glucose tolerance test

INTRODUCTION

Delayed separation of red cells from plasma causes pre analytical glucose loss, which in turn results in an under-diagnosis of GDM (gestational diabetes) based on the OGTT (oral glucose tolerance test). In silico investigations may help laboratory decision making, when exploring pragmatic improvements to sample processing.

METHODS

Late pregnancy 0, 1 and 2h 75g OGTT values were obtained from two distinct populations of pregnant women: 1. Values derived from the HAPO (Hyperglycemia and Adverse Pregnancy Outcome) Study and 2. New Zealand women identified as at higher risk of GDM by their caregivers, undergoing OGTT during routine antenatal care. In both populations studied, in silico modelling focussed on the effects of pre-analytical delays in plasma separation, when using fluoride collection tubes.

RESULTS

Using a model that 'batched' samples from the three OGTT collection times, diagnostic sensitivity was estimated as follows: 66.1% for HAPO research population and 48.4% for the 1305 women receiving routine antenatal care. If samples were not batched, but processed shortly after each blood sample was collected, then sensitivity increased to 81%.

CONCLUSION

Exploration of a range of clinical and laboratory scenarios using in silico modelling, showed that delaying the processing of pregnancy OGTT samples, using batched sample collection into fluoride tubes, causes unacceptable loss of GDM diagnostic sensitivity across two distinct population groups. This modelling approach will hopefully provide information that helps with final decision making around improved laboratory processing techniques.

Applying ethnic-specific bone mineral density T-scores to Chinese women in the USA

Caucasian reference data are used to classify bone mineral density in US women of all races. However, use of Chinese American reference data yields lower osteoporosis prevalence in Chinese women. The reduction in osteoporosis labeling may be relevant for younger Chinese women at low fracture risk.

INTRODUCTION

Caucasian reference data are used for osteoporosis classification in US postmenopausal women regardless of race, including Asians who tend to have lower bone mineral density (BMD) than women of white race. This study examines BMD classification by ethnic T-scores for Chinese women.

METHODS

Using BMD data in a Northern California healthcare population, Chinese women aged 50-79 years were compared to age-matched white women (1:5 ratio), with femoral neck (FN), total hip (TH), and lumbar spine (LS) T-scores calculated using Caucasian versus Chinese American reference data.

RESULTS

Comparing 4039 Chinese and 20,195 white women (44.8 % age 50-59 years, 37.5 % age 60-69 years, 17.7 % age 70-79 years), Chinese women had lower BMD T-scores at the FN, TH, and LS (median T-score 0.29-0.72 units lower across age groups, p < 0.001) using Caucasian reference data. Using Chinese American BMD reference data resulted in an average +0.47, +0.36, and +0.48 units higher FN, TH, and LS T-scores, respectively, reducing the prevalence of osteoporosis (T-score ≤ -2.5) in Chinese women at the FN (16.7 to 6.6 %), TH (9.8 to 3.2 %), and LS (23.2 to 8.9 %); osteoporosis prevalence at any one of three sites fell from 29.6 to 12.6 % (22.4 to 8.1 % for age 50-64 years and 43.2 to 21.0 % for age 65-79 years).

CONCLUSION

Use of Chinese American BMD reference data yields higher (ethnic) T-scores by 0.4-0.5 units, with a large proportion of Chinese women reclassified from osteoporosis to osteopenia. The reduction in osteoporosis labeling with ethnic T-scores may be relevant for younger Chinese women at low fracture risk.

Determination of high-sensitivity cardiac troponin I 99th percentile upper reference limits in a healthy Korean population

OBJECTIVES

This study aimed to determine the 99th percentile upper reference limit (URL) concentration of cardiac troponin I (cTnI) with a high-sensitivity assay in a Korean population.

DESIGN AND METHODS

Cardio-healthy males and females were enrolled between March 2014 and March 2015. Participants with possible subclinical conditions were excluded on the basis of laboratory measures (primary: estimated glomerular filtration rate and glycated hemoglobin; secondary: B-type natriuretic peptide). Serum cTnI was measured using ARCHITECT STAT High-Sensitive Troponin-I Assay (Abbott Diagnostics, USA).

RESULTS

A total of 1204 participants completed a self-reporting questionnaire for inclusion in the study. Of these, we excluded 349 (29.0%) participants on the basis of primary (n=283) and secondary (n=66) laboratory measures. Ultimately, we included 854 participants (mean age, 49.8±10.2years) in the final analysis. The 99th percentiles of cTnI concentrations were 18 (90% confidence interval [CI], 14-35) ng/L for all participants, 20 (90% CI, 15-69) ng/L for males and 19 (90% CI, 11-41) ng/L for females. In both males and females, the median cTnI concentrations were significantly higher in participants aged 50years and older than in those younger than 50years old.

CONCLUSIONS

In this study, the reference population with Korean ethnicity had lower overall and male 99th percentile URLs than other reference populations. Our data suggest that 99th percentile URLs may be influenced by factors such as ethnicity, age distribution of participants, and selection criteria used to define a healthy reference population.

The incidence of colon cancer among patients diagnosed with left colonic or sigmoid acute diverticulitis is higher than in the general population

BACKGROUND

Considering the low incidence of colon cancer after an initial episode of colonic diverticulitis in some categories of patients, some authors suggested to exempt them from colonoscopy. However, this incidence has never been compared to that of a reference population, and predictors of cancer are still poorly investigated. We aimed to determine the 1-year incidence of colon cancer at the site of diverticulitis in patients diagnosed with left colonic or sigmoid acute diverticulitis, to compare this incidence to a reference population to state whether endoscopy is required or not, and to identify predicting factors of cancer to better target subpopulations needing that examination.

METHODS

All patients admitted at the University Hospitals of Geneva for left colonic or sigmoid acute diverticulitis were included. Patients with a previous history of colon cancer or non-available for follow-up were excluded. Demographic data, haemoglobin values, and the Hinchey score were documented. This cohort was matched with the Geneva Cancer Registry to look for cancer occurrence at the site of diverticulitis within 1 year. Predictors of cancer were assessed using univariate logistic regression and the risk of cancer by comparing observed cases to a reference population using standardized incidence ratios.

RESULTS

The final cohort included 506 patients. Eleven (2.2 %) had a diagnosis of cancer at the site of diverticulitis within 1 year. The mean age was significantly different between patients with cancer and others. No predictor of cancer could be identified, except a trend for an increased risk with advancing age (p = 0.067). The standardized incidence ratios showed a 44-fold increased risk of cancer among the cohort compared to the reference population.

CONCLUSIONS

Colonoscopy should be continued after an initial diagnosis of left colonic or sigmoid acute diverticulitis, irrespective of the clinical or radiological presentations.

The calculation of the cardiac troponin T 99th percentile of the reference population is affected by age, gender, and population selection: a multicenter study in Italy

BACKGROUND

The aim of this study is to determine the 99th upper-reference limit (URL) for cardiac troponin T (cTnT) in Italian apparently healthy subjects.

METHODS

The reference population was selected from 5 cities: Bolzano (n=290), Milano (CAMELIA-Study, n=287), Montignoso (MEHLP-Study, n=306), Pisa (n=182), and Reggio Calabria (MAREA-Study, n=535). Subjects having cardiac/systemic acute/chronic diseases were excluded. Participants to MEHLP project underwent cardiac imaging investigation. High-sensitive cTnT was measured with Cobas-e411 (Roche Diagnostics).

RESULTS

We enrolled 1600 healthy subjects [54.6% males; age range 10-90years; mean (SD): 36.4 (21.2) years], including 34.6% aged <20years, 54.5% between 20 and 64years, and 10.9% over 65years. In the youngest the 99th URL was 10.9ng/L in males and 6.8ng/L in females; in adults 23.2ng/L and 10.2ng/L; and in elderly 36.8ng/L and 28.6ng/L. After the exclusion of outliers the 99th URL values were significantly decreased (P<0.05) in particular those of the oldest (13.8ng/L and 14ng/L). MEHLP participants were divided in healthy and asymptomatic, according to known cardiovascular risk factors (HDL, LDL, glucose, C-reactive protein): the 99th URL of cTnT values of these subgroups was significantly different (19.5 vs. 22.7, P<0.05).

CONCLUSIONS

99th URL of cTnT values was strongly affected by age, gender, selection of subjects and the statistical evaluation of outliers.

Effect of population selection on 99th percentile values for a high sensitivity cardiac troponin I and T assays

OBJECTIVE

Using objective laboratory and clinical criteria to more accurately determine the 99th percentile values for cardiac troponin I and T.

DESIGN AND METHODS

We measured cardiac troponin T and cardiac troponin I with high-sensitivity assays in a large cohort of apparently healthy community subjects and calculated 99th percentiles for different sexes and ages. Subjects with possible subclinical disease were eliminated based on objective laboratory criteria, eGFR and NT-proBNP, and clinical criteria, history and examination and echocardiogram.

RESULTS

For men and women of all ages, separately, more than 50% of subjects were excluded using these criteria, with a lesser proportion of younger subjects being excluded. In men aged <75 years, the 99th percentile for cTnI decreased by more than 50% from 22.9 ng/L to 10.3 ng/L. In other age groups and for cTnT the decrease was smaller (%) but still considerable.

CONCLUSIONS

For establishing cardiac troponin 99th percentiles, simply using self-reporting of health is insufficient. Objective laboratory measures and clinical and echocardiographic assessments are essential to define a healthy population, especially in older persons.