External quality assessment providers' services appear to more impact the immunohaematology performance of laboratories than national regulatory and economic conditions.

OBJECTIVES: Medical laboratories may, at their own discretion, exceed but not undercut regulatory quality requirements. Available economic resources, however, may drive or hinder eagerness to exceed minimum requirements. Depending on the respective scopes of regulatory and economic framework conditions, differing levels of quality efforts to safeguard laboratory performance can be anticipated. However, this has not yet been investigated. METHODS: Immunohaematology external quality assessment (EQA) results collected by 26 EQA providers from their participant laboratories in 73 countries from 2004 to 2019 were evaluated. Error rates were aggregated in groups according to the respective national regulatory and economic framework conditions, to whether or not expert advice was provided in case of incorrect results, and the frequency of EQA samples. RESULTS: These representative data indicate no association between national regulatory (mandatory participation in EQA, monitoring of performance of individual laboratories by authorities, financial consequences of incorrect results) and economic (level of national income, share of national health expenditure) conditions to the quality performance of medical laboratories in immunohaematology. However, EQA providers' support for laboratories in the event of incorrect results appear to be associated with lower error rates, but a high EQA sample frequency with higher error rates. CONCLUSIONS: Further research into the impact of introducing or changing services of EQA providers is needed to confirm the results found in this first of its kind study.

Alternative Sample-Homogeneity Test for Quantitative and Qualitative Proficiency Testing Schemes.

Proficiency Testing (PT) External Quality Assessment (EQA) schemes are designed to ascertain the ability of individual laboratories to perform satisfactorily with respect to their peer laboratories or to limits imposed by external sources. Observed deviation of a laboratory result for a PT sample must be entirely attributed to the laboratory and not to the PT provider. To minimize the probability that deviations could be attributed to the PT provider, sample homogeneity should be assured. It is generally required that for quantitative parameters, the standard deviation among PT units should be calculated on the basis of duplicate measurements of at least 10 samples chosen at random, and the standard deviation among PT units should not exceed 0.3 times the standard deviation used to evaluate laboratories. Because this approach has important drawbacks, an alternative procedure is proposed by applying the theory of acceptance sampling to the assessment of sample heterogeneity for both quantitative and qualitative data and deriving acceptance limits on the basis of minimizing the probability of falsely evaluating laboratories. For obtaining acceptance limits for quantitative parameters, a distinction is made between laboratory evaluation using fixed limits on the one hand and laboratory evaluation using limits that are based on the variability of the reported results on the other hand. Sequential tests are proposed to evaluate sample heterogeneity by means of a comparison with the χ2 distribution. For qualitative parameters, acceptance-sampling plans are proposed that are based on minimizing the joint probability of rejecting batches that have a satisfactory amount of defective samples and accepting batches unnecessarily. The approach for quantitative parameters is applied on samples for a PT scheme of ethanol quantification and for qualitative parameters on the presence of monoblasts in a blood smear. It was found that five samples could already be enough to prove that the batch was homogeneous for quantitative parameters, although more than 20 samples were needed to prove homogeneity for qualitative parameters. This study describes a direct relation among the objective of an PT round, the criteria for evaluating the results, and the sample heterogeneity. When samples are effectively homogeneous, less measurements are needed than current practices require. A drawback of the proposed approach is that the number of samples to be tested is not known beforehand, and good knowledge of the analytical variability is crucial. The formulas to be applied are relatively simple. Despite the drawbacks, the proposed approach is generally applicable for both quantitative and qualitative data.

Distribution of HCV genotypes in Belgium from 2008 to 2015.

BACKGROUND: The knowledge of circulating HCV genotypes and subtypes in a country is crucial to guide antiviral therapy and to understand local epidemiology. Studies investigating circulating HCV genotypes and their trends have been conducted in Belgium. However they are outdated, lack nationwide representativeness or were not conducted in the general population. METHODS: In order to determine the distribution of different circulating HCV genotypes in Belgium, we conducted a multicentre study with all the 19 Belgian laboratories performing reimbursed HCV genotyping assays. Available genotype and subtype data were collected for the period from 2008 till 2015. Furthermore, a limited number of other variables were collected: some demographic characteristics from the patients and the laboratory technique used for the determination of the HCV genotype. RESULTS: For the study period, 11,033 unique records collected by the participating laboratories were used for further investigation. HCV genotype 1 was the most prevalent (53.6%) genotype in Belgium, with G1a and G1b representing 19.7% and 31.6%, respectively. Genotype 3 was the next most prevalent (22.0%). Further, genotype 4, 2, and 5 were responsible for respectively 16.1%, 6.2%, and 1.9% of HCV infections. Genotype 6 and 7 comprise the remaining <1%. Throughout the years, a stable distribution was observed for most genotypes. Only for genotype 5, a decrease as a function of the year of analysis was observed, with respectively 3.6% for 2008, 2.3% for 2009 and 1.6% for the remaining years. The overall M:F ratio was 1.59 and was mainly driven by the high M:F ratio of 3.03 for patients infected with genotype 3. Patients infected with genotype 3 are also younger (mean age 41.7 years) than patients infected with other genotypes (mean age above 50 years for all genotypes). The patients for whom a genotyping assay was performed in 2008 were younger than those from 2015. Geographical distribution demonstrates that an important number of genotyped HCV patients live outside the Belgian metropolitan cities. CONCLUSION: This national monitoring study allowed a clear and objective view of the circulating HCV genotypes in Belgium and will help health authorities in the establishment of cost effectiveness determinations before implementation of new treatment strategies. This baseline characterization of the circulating genotypes is indispensable for a continuous surveillance, especially for the investigation of the possible impact of migration from endemic regions and prior to the increasing use of highly potent direct-acting antiviral (DAA) agents.

The C677T MTHFR genotypes influence the efficacy of B9 and B12 vitamins supplementation to lowering plasma total homocysteine in hemodialysis.

BACKGROUND: Hyperhomocysteinaemia, an independent risk factor for cardiovascular diseases, is common in hemodialysis patients (HD) and particularly in those homozygous for polymorphism of the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene. B vitamins supplementation has been shown to lower plasma total homocysteine (tHcy), but this has been contreversed in several groups. The aim of our study was to explore the response of tHcy in hemodialysis (HD) patients to individual supplementation with folic acid (B9) and/or vitamin B12, based on carrier status for the (MTHFR) polymorphism. METHODS: 132HD were randomized according to C677TMTHFR genotypes into 2 groups (AandB). The group (A) was treated initially with B9 (10mg/day orally) for 2 months (t1) and then with B12 vitamin (cyanocobalamin ampoule of 1000 µg) for the following 2 months (t2), then association of B9 and B12 for 2 months (t3). The group (B) was supplemented initially with vitamin B12 (t1), then with folic acid (t2) and then B9 + B12 for 2 months (t3). A wash-out period of 2 months followed the treatment in both groups (t4). We determined tHcy, B9 and B12 concentrations at each time. RESULTS: In group A, we noted that the decrease in tHcy becomes significant for CC when patients were supplemented with vit B12 only (p = 0.009). While, B9 + vit B12 supplementation did not seem to improve a significant effect compared with B12 alone. For genotypes (CT) and (TT) we noticed a significant decrease in tHcy at t1 (p = 0.038; 0.005 respectively) and at (t3; CT p = 0.024; TT p = 0.017). In group B, for genotypes CC, the decrease in tHcy became significant at t3 (vit B12 + B9; p = 0.031). For genotypes (CT) and (TT), at the replacement of vit B12 by B9, tHcy was significantly decreased (p = 0.036; 0.012, respectively). The combination of the 2 vitamins (t3) showed no difference compared to folate alone. In the 2 groups (t4), there was an significant increase of tHcy again for 3 genotypes. CONCLUSION: Supplementation with B vitamins correlated to the MTHFR genotypes has been shown to lower significantly tHcy in HD patients.