Sensitivity and specificity of copper sulphate test in determining fitness of blood donors

Background: The accuracy of the copper sulphate method for the rapidscreening of prospective blood donors has been questioned because this rapid screening method may lead to false deferral of truly eligible prospective blood donors.Objective: This study was aimed at determining the sensitivity and specificity of copper sulphate specific gravity test for haemoglobin estimation as a determinant of fitness for blood donation at Lagos University Teaching Hospital, Lagos, Nigeria (LUTH).Methods: This study was a case control study carried out at LUTH between March and April, 2012. Subjects (n=263) recruited were classified into unfit donors/study group (n=153) and fit donors/control group (n=110). 5ml of venous blood withdrawn from each subject in EDTA bottle were used for full blood count analysis using the Haemoglobin auto-analyzer (Sysmex KX21, USA®) as a reference test for Haemoglobin determination.Results: The mean Haemoglobin, PCV and MCHC of the control group were significantly higher (P<0.05) than that of the study group. MCV and MCH were not significantly different (P>0.05). The sensitivity and specificity of the copper sulphate specific gravity method were found to be 40.52% and 86.4% respectively while the positive and negative predictive values were 80.5% and 50.1% respectively.Conclusion: The sensitivity, specificity, PPV and NPV of Copper sulphate test to determine fitness of donation were too low to recommend it. It is recommended that more sensitive methods such as automated haematology analyzer should be encouraged.Keywords: Copper Sulphate specific gravity method, Blood donors, Haemoglobi

An evaluation of Quasi-Moment-Method calibrated pathloss models for Benin City Nigeria

This paper introduces the Quasi-Moment-Method (QMM) as a novel radiowave propagation pathloss model calibration tool, and evaluates its performance, using field measurement data from different cellular mobile communication network sites in Benin City, Nigeria. The QMM recognizes the suitability of component parameters of existing basic models for the definition of ‘expansion’ and ‘testing functions’ in a Galerkin approach, and simulations were carried out with the use of a FORTRAN program developed by the authors, supported by matrix inversion in the MATLAB environment. Computational results reveal that in terms of both Root Mean Square (RMS) and Mean Prediction (MP) errors, QMM-calibrated models performed much better than an ‘optimum’ model reported for the NIFOR (Benin City), by a recent publication. As a matter of fact, the QMM-calibrated COST231 (rural area) model recorded reductions in RMS error of between 31.5% and 71% compared with corresponding metrics due to the aforementioned ‘optimum’ model. The simulation results also revealed that of the five basic models (COST231-rural area and suburban city, ECC33 (medium and large sized cities), and Ericsson models) utilized as candidates, the two ECC33 models, whose performances were consistently comparable, represented the best models for QMM-model calibration in the Benin City environments investigated