EVALUATION OF HEMOCHROMA POC Hb READER Investigators: Mr. Francis M Wanyama 1, Prof Christine S. Kigondu1 and Dr. Peter Maturi2   Department of Human Pathology, School of Medicine, University of Nairobi, 1Clinical Chemistry Section, 2Hematology and BTU Section, P.O Box 19676 – 00202, Nairobi, Kenya.

INTRODUCTION Boditech’s Hemochroma TM is a portable hemoglobin meter based on robust and reliable detection mechanism with proper handling. It is capable of delivering excellent accurate measurements comparable to high end reference hemoglobin analyzers.

RATIONALE GLP requires that all equipment upon installation should demonstrate the capability of achieving the performance required as well as complying with the specifications relevant to the tests concerned. All methods have to be validated extensively in order to confirm that they are suitable for the intended use. Laboratories are expected to carry out thorough investigations of their analyzer as part of method validation before they are put into use.

STUDY OBJECTIVE To assess the performance of Boditec’s Hemochroma TM Point of care (POC) hemogloblin reader with respect to its level of accuracy.

MATERIAL AND METHODS Test Equipment: Boditec’s hemochroma Hemochroma TM POC hemoglobin reader is developed for the quantitative assay of hemoglobin in human blood by standard cyanmethemoglobin method.

Comparative Equipment: aᶜ.T 5 differential CP analyzer Beckman Principle: It is a fully automated hematology analyzer providing a complete WBC five-part differential which is determined simultaneously by the ACV(absorbance, cytochemistry and volume technology ) and is focused flow impedance

Beckman HB measurement It is based on transmittance of light through the optical part of the first dilution/Hb bath using spectrophotometric technique at wavelength of 550nm. The transmittance of the sample dilution is compared to the transmittance of a reagent blank. The system calculates the Hb using the blank and sample readings.

The cyanmethemoglobin method The Hb released by lysis of RBC combines with the potassium cyanide to form a stable cyanmethemoglobin compound which is measured through optical part of the first dilution/Hb bath using spectrophotometric technique at a wavelength of 550nm.

Table: Technical characteristics for measurement of Hb Dilution characteristic  Volume of whole blood - 10µl Volume of Aᶜ.T differential diluent - 1700µl Preliminary dilution ratio - 1:170 Volume of the 1:170 dilution removed(for making the RBC/platelet dilution) - 42.5µl Volume of Aᶜ.T 5 differential Hb lyse - 400µl Additional volume of Aᶜ.T 5 differential diluent - 400µl Final dilution for Hb determination - 1:250 Reaction temperature - 35⁰C(95⁰F) Methods of analysis - spectrophotometry Wavelength - 550nm 

RELATIVE ACCURACY The comparative equipment used was Beckman coulter Ac TTM Haematology analyser PN 4237650c from Beckman coulter Inc, Fullerton, CA 92 835.

STATISTICAL ANALYSIS The data was analyzed statistically by use of SD, the CV and finally the results were subjected to the students ‘t’ test to test for variance and correlation. t = X1- X/SE critical values also known as ‘t’ tabulated, which tests significance [P] was obtained from the standard statistical tables

  RESULTS The Hb (g/dl) levels for 52 specimen as read on Beckman and Hemochroma TM POC and the resultant means, SD and CV% Comparative Hb levels were obtained using factor -1.7 between the Beckman and Hemochroma. Intra sample standard deviation obtained between the two machines were within 1 SD with mean SD of 0.4

Coefficient of variation (C. V%) ranged between 0 and 11 Coefficient of variation (C.V%) ranged between 0 and 11.0 per cent with only 8 points out of 52 giving above 6%. The mean C.V was 3.2% which is within the acceptable of up to 6% The student ‘t’ test gave P value of <0.0005, this shows that there is no significant statistical difference between the two methods

CONCLUSION The mean levels of Hb (g/dl) for Beckman and Hemochroma POC was 12.1 and 11.6 respectively with mean of both two level at 11.9 and 1SD of 0.4. The student ‘t’ test showed P. value of < 0.0005 showing that the two means were not statistically different when a factor of -1.7 was used. The correlation coefficiency [r] was 0.9 indicating that the two methods are highly correlated.

RECOMMENDATIONS Periodic calibration should be inbuilt based on an internal quality control and/or reference methods. The identified places where the machine can be of greater use includes Casualty Wards, Antenatal clinic, Medical clinics eg for Heamatological clinic, Research, Screening camps, Mobile clinics and Laboratories in the rural settings etc.

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