An Assessment of the Accuracy of Creatinine Measurements in Guyana

ABSTRACT Background: The incidence of chronic kidney disease (CKD) is relatively high in Guyana. Estimated glomerular filtration rate (eGFR) reporting allows for early-stage CKD identification when therapeutic interventions can prevent CKD progression. Accurate creatinine measurements are essential for valid eGFR calculations. Objective: This study was undertaken to assess the accuracy of creatinine measurements in Guyana prior to implementing routine eGFR reporting. Methods: Sixteen Guyanese laboratories participated in this study. Each laboratory received a common set of blinded human serum samples (n = 3) containing clinically relevant creatinine concentrations, assigned by an international reference method (ID-GCMS). Laboratories performed repeated measurements of creatinine in each sample. These data were used to calculate bias, precision and total error (TE) for each creatinine method. Linear regression was used to compare measured creatinine results to assigned reference sample values and to post-analytically correct calibration bias, a priori, for recent patient results from each laboratory. Patient eGFR profiles were compared before and after bias correction. Results: The mean across samples CV and bias for all labs were 9% (range 2.5%-39.3%) and 11% positive (range 0.4%-29.1%), respectively. The mean TE was 28.6%. If the mean TE from a subset of the better performing laboratories (CV < 7%) was to apply nationally, an 'all stage' eGFR misclassification rate of 36% would result. Conclusion: There is a pressing need to improve the accuracy of creatinine measurements in Guyana as, at this time, routine reporting of eGFR by Guyanese laboratories cannot be recommended based on the accuracy data presented in this study.

A case series of Factor V Leiden mutation in pregnancy

Background. Pregnant patients with Factor V Leiden (FVL) mutation are at an increased risk of venous thromboembolic disease (VTED) and placental-mediated complications. Thromboprophylaxis with low-molecular-weight heparin (LMWH) can potentially mitigate these risks. Objective. To describe the clinical course of a cohort of patients with FVL mutation with different underlying genotypes.Methods. The pregnancy outcomes, occurrence of VTED events and laboratory test results of pregnant women with FVL mutation managed at a quaternary medical centre over a period of 18 years in Johannesburg, South Africa, were analysed. Results. Over the period of analysis, 25 pregnant women with FVL mutation were referred to the haematology department for management. Ten patients (40%) had a family history, and 15 patients (60%) a personal history of VTED. The majority of provoked VTED events (90%) were secondary to combined oral contraceptive exposure. Previous pregnancy loss occurred in 4 (16%) patients, of whom 3 (75%) suffered recurrent losses. All women received prophylactic anti-Factor Xa (anti-FXa) dose-adjusted LMWH during ante- and postnatal periods. All pregnancies resulted in live births with 1 VTED event recorded. Conclusion. Patients with FVL mutation show phenotypical heterogeneity in terms of pregnancy outcomes, VTED events and placental-mediated complications. Confounders contributing to the heterogeneity are not completely defined and deciding on appropriate treatment is not fully standardised but the live birth rate is encouraging