Brand of dipotassium EDTA vacuum tube as a new source of pre-analytical variability in routine haematology testing.

This study assesses the use of different dry K2 (dipotassium) EDTA vacuum tubes and whether or not they might represent a bias in haematological testing. Blood was collected in three dipotassium EDTA vacuum tubes from different manufacturers: Venosafe, Vacuette and Vacutainer. Samples were analysed on an Advia 2120i analyser. Significant differences among results and biases were compared with current quality specifications. Significant differences were found for haematocrit (HCT), mean corpuscular volume (MCV), white blood cell count (WBC) and platelet distribution width (PDW) when comparing Venosafe vs. Vacuette; for MCV, WBC and PDW when comparing Venosafe vs. Vacutainer; and for HCT and MCV when comparing Vacuette vs. Vacutainer. Clinically significant variations were observed for HCT and PDW in Venosafe vs. Vacuette; PDW in Venosafe vs. Vacutainer; and HCT and MCV in Vacuette vs. Vacutainer. The use of dipotassium EDTA vacuum tubes from different manufacturers represent a clinically relevant source of variation for HCT, MCV and PDW.

The influence of the tourniquet time on hematological testing for antidoping purposes.

Hematological manipulation to optimize aerobic performances is a serious problem in elite and professional sports and the approach to identify blood doping is as yet challenging. In most cases, the current strategy contemplates a first stage of analysis, based on the application of arbitrary threshold for hemoglobin or hematocrit, followed by second-generation blood tests, or the adoption of an individual hematological passport. To establish the influence of preanalytical variables on the athletes' hematological profile, we compared hemoglobin, hematocrit, and reticulocytes count in 27 male professional cyclists after a mean time of 2.30 +/- 0.12 tourniquet holding. Statistically significant differences were observed for hematocrit (+ 2.4 %; p < 0.001) and hemoglobin measurements (+ 1.4 %; p < 0.001), but not for the reticulocytes count (- 1.9 %; p = 0.170). In 4 out of 27 cases (15 %), the variability of the hematocrit measurement exceeded the 4.1 % desirable analytical quality specification for total error. Results of the present investigation further highlight the risk that unfulfillment of rigorous and standardized procedures for collection of blood specimens might increase the number of false positive testing and might lead to inappropriate sanctioning of a minority of clean athletes with hematocrit or hemoglobin values naturally elevated. Owing to the minor biological variability and the lesser susceptibility to variation of the preanalytical phase, the hemoglobin concentration might be a more suitable parameter than hematocrit for inclusion within laboratory testing to identify blood doping.

Complex glycerol kinase deficiency leads to psychomotor and body-growth failure.

Complex glycerol kinase deficiency usually presents with Duchenne muscular dystrophy, glycerol kinase deficiency and adrenal hypoplasia congenital. We describe a follow-up patient with complex glycerol kinase deficiency who had appropriate intrauterine development, but who at 1 month of age manifested severe growth delay and psychomotor retardation. Targeted therapy did not bring about the regression of symptoms: both bodyweight and height were below the 3rd centile until 8 years of age, and his Griffith's Mental Development scale score was 71 at age 5 years.

The role of iron status markers in predicting response to intravenous iron in haemodialysis patients on maintenance erythropoietin.

BACKGROUND: Iron deficiency (ID) is the main cause of hyporesponsiveness to erythropoietin in haemodialysis patients and its detection is of value since it is easily corrected by intravenous iron. Markers of iron supply to the erythron, including erythrocyte zinc protoporphyrin (Er-ZPP), percentage of hypochromic erythrocytes (Hypo), reticulocyte haemoglobin content (CHr) and soluble transferrin receptor (sTfR), may be more accurate predictors of ID than ferritin (Fer) and transferrin saturation (TSat), but relative diagnostic power and best threshold values are not yet established. METHODS: In 125 haemodialysis patients on maintenance erythropoietin, the diagnostic power of the above parameters was evaluated by ROC curve, multivariate regression, and stepwise discriminant analyses. Diagnosis of ID was based on haemoglobin response to intravenous iron (992 mg as sodium ferric gluconate complex over an 8-week period). RESULTS: Fifty-one patients were considered iron deficient (haemoglobin increase by 1.9+/-0.5 g/dl) and 74 as iron replete (haemoglobin increase by 0.4+/-0.3 g/dl). ROC curve analysis showed that all tests had discriminative ability with the following hierarchy: Hypo (area under curve W=0.930, efficiency 89.6% at cut-off >6%), CHr (W=0.798, efficiency 78.4% at cut-off < or =29 pg), sTfR (W=0.783, efficiency 72.4% at cut-off >1.5 mg/l), Er-ZPP (W=0.773, efficiency 73.0% at cut-off >52 micromol/mol haem), TSat (W=0.758, efficiency 70.4% at cut-off <19%) and ferritin (W=0.633, efficiency 64.0% at cut-off <50 ng/ml). Stepwise discriminant analysis identified Hypo as the only variable with independent diagnostic value, able to classify 87.2% of patients correctly. Additional tests did not substantially improve diagnostic efficiency of Hypo >6% alone. CONCLUSIONS: In haemodialysis patients on maintenance erythropoietin, Hypo >6% is the best currently available marker to identify those who will improve their response after intravenous iron. Cost-effectiveness suggests that this parameter should be a first-line tool to monitor iron requirements in clinical practice.