Effect of different haemoglobins on the glucose 6 phophate dehydrogenase deficiency screening test (brewer's test)
Date
2002-10-30
Authors
Sugathadasa, B. H. K. R.
Perera, P. A. J.
Dissanayake, D. M.
Journal Title
Journal ISSN
Volume Title
Publisher
The university of Peradeniya
Abstract
Glucose 6-phosphate dehydrogenase (G6PD) deficiency is the commonest enzymopathy causing haemolytic anemia in humans. Haemoglobinopathies too contribute towards haemolytic anemia in Sri Lanka. The laboratory investigations of chronic haemolytic anaemia include, screening test and enzyme assay to exclude G6PD deficiency. Haemoglobinopathies and thalassaemic syndromes are excluded by haemoglobin electrophoresis. Even though G6PD enzyme assay is indicated for diagnosis of G6PD deficiency, due to lack of reagents all the government hospitals in Sri Lanka employ only the screening test (Brewer's test) for the diagnosis.
The aim of the study is to observe the effect of different haemoglobins on screening test for G6PD deficiency. We investigated patients & carriers for haemoglobinopatheis (Hb E, Hb S, Hb D) using G6PD deficiency screening test as well as G6PD enzyme assay.
The results show that Haemoglobin E present in Haemoglobin Elf} thalassemia, Haemoglobin E trait and Haemoglobin E disease, gives a false positive reaction with G6PD screening test. Forty-four out of forty nine subjects (93.9%) with haemoglobin E were positive for G6PD screening test, even though their G6PD enzyme levels were normal, Two subjects showed low enzyme levels with positive screening test. Only three out of forty nine (6.2%) were negative for G6PD screening test. Haemoglobin S (n=5) and Haemoglobin D (n=2) did not show any effect on the screening test for G6PD deficiency.
Haemoglobin E is the commonest haemoglobinopathy in Sri Lanka, with high prevalence in Kurunegala, Anuradhapura and Chilaw districts. If only the screening test is utilized in the diagnosis of G6PD deficiency, the patients with Haemoglobin E are likely to be labeled as G6PD deficient, while having normal enzyme levels. Therefore G6PD enzyme assay should be used in the diagnosis of G6PD deficiency, at least in districts with high Haemoglobin E prevalence.
Description
Keywords
Citation
Proceedings and Abstract of the Annual Research Sessions, October 30,2002, University of Peradeniya, Sri Lanka P 106