Validation of the haemoglobin colour scale for screening blood donors in Malawi

Background In 2009 Malawi introduced a new protocol to screen potential blood donors for anaemia, using the WHO Haemoglobin Colour Scale (HCS) for initial screening. Published studies of the accuracy of the HCS to screen potential blood donors show varying levels of accuracy and opinion varies whether this is an appropriate screening test. The aim of the study was to assess the validity of the HCS, as a screening test, by comparison to HemoCue in potential blood donors in Malawi. Study design and Methods This was a blinded prospective study in potential blood donors aged over 18 years, at Malawi Blood Transfusion Service in Blantyre, Malawi. Capillary blood samples were analysed using the HCS and HemoCue, independent of each other. The sensitivity and specificity of correctly identifying ineligible blood donors (Hb≤12g/dL) were calculated. Results From 242 participants 234 (96.7%) were correctly allocated and 8 (3.3%), were wrongly allocated on the basis of the Haemoglobin Colour Scale (HCS) compared to HemoCue, all were subjects that were wrongly accepted as donors when their haemoglobin results were ≤12.0g/dL. This gave a sensitivity of 100% and specificity of 96.7% to detect donor eligibilty. The negative predictive value of the HCS was 100% but the positive predictive value to identify ineligible donors on the basis of anaemia was only 20%. Conclusions Initial screening with the HCS correctly predicts eligibility for blood donation in the majority of potential blood donors at considerable cost saving compared with use of HemoCue as the first line anaemia screening test, however, by this method a small number of anaemic patients were allowed to donate blood.

Pre-Discharge Screening Trans-Cutaneous Bilirubinometry in Healthy Newborns in Mahdieh Hospital, Tehran

Background: Incidence of jaundice is high in newborn infants. Since well appearing newborns are rapidly and routinely discharged from hospital, performing an inexpensive noninvasive pre-discharge screening test for evaluation of jaundice seems to be necessary. Objectives: This study was conducted to compare the accuracy of cutaneous v/s serum bilirubin measurements in this regard. Patients and Methods: This was a prospective cross sectional study conducted in Mahdieh hospital, Tehran. 613 neonates weighing ≥ 1,800 g with gestational age of ≥ 35 weeks were enrolled. A pre discharge transcutaneous bilirubin test (TcB) was performed in all. Serum samples were taken from neonates with TcB ≥ 5 mg/dL in first and > 8 mg/dL in second 24 hours. Decision for treatment or recheck of bilirubin level after discharge was made based on serum bilirubin results. Results: Based on the study protocol, among 613 studied neonates, 491 (80%) revealed high TcB, of them 240 (49%) cases showed TBC ≥ 5 mg/dL in first and 251 (51 %) in second pre-discharge 24 hours. TcB ranged 3.3 - 17.1, mean TcB in first 24 hours was 6.9 ± 1 .7 (mode 6) and in second 24 hours 9.1 ± 2.1 (mode 10). Of 491 neonates with high TcB, capillary serum sample was taken as the second step and 398 neonates revealed high total serum bilirubin (TsB) with the same protocol for TcB. 108 (27.1%) neonates showed TsB ≥ 5 mg/dL in first and 290 (72.9%) in second 24 hours. According to the study results TcB has a 81% positive predictive value (PPV) in diagnosis of hyperbilirubinemia. Correlation coefficient of TcB and TsB in highest rate is equal to 72% (P value < 0.001). Conclusions: TcB is an inexpensive, noninvasive and precise pre-discharge screening test for evaluation of hyperbilirubinemia, with a high PPV. It is highly recommended to be performed routinely due to high incidence of hyperbilirubinemia in neonates.