Studies On G6PD Stability In Blood Stored With Different Anticoagulants

摘要

Background: G - 6PD screening is not carried out on overnight K2EDTA anticoagulated blood samples in our hospital. This was due to belief that the G6PD enzyme would have lost its activity. Literature datas on stability of G6PD in blood stored with different anticoagulants varied from one author to another. Objectives: To investigate the viability of G6PD in blood stored with different anticoagulants.Setting: The work was undertaken in the special Investigation unit of the department of Haematology Obafemi Awolowo University Teaching Hospital Complex, Ile-Ife, Nigeria.Methodology: G6PD screening was performed using methaemogobin reduction method on 100 apparently health Nigerians. Their blood samples were collected into dispotassium ethlenediamine tetraacetic acid (K2EDTA); acid citrate dextrose, (ACD); citrate phosphate dextrose (CPD); sodium citrate, lithium heparin, ammonium oxalate and Fluoride oxalate. The tests were performed within an hour of blood collection, the blood samples were them kept at 4°c and the tests repeated at 12, 24, 48 and 72 hours of storage.Result and conclusion: the result of G6PD screening within an hour of blood collection and at 12, 24, 48 and 72 hours after storage at 4°c in K2EDTA, ACD, CPD, sodium citrate and lithium heparin were the same. The results of G6PD screening within an hour of blood collection and 12 hours after storage at 4°c in ammonium oxalate at 24, 48 and 72 hours in the oxalates. G6Pd was stable for up to 72 at 4°c in K2EDTA, ACD, CPD, sodium citrate and lithium heparin and just for 12 hours in the oxalates, Introduction Glucose- 6- phosphate is a cytosolic enzyme that generates reduced nicotinamide adenine dinuclueotide phosphate (NADPH) in the oxidative branch of the pentose phosphate pathway (PPP) (Salvemini and France, 1997) The clinical significance of G6PD is the deficiency state which is an inheritable sex-linked recessive disorder whose primary effect is the oxidation of double bonds in the red cell membrane to epoxide by hydrogen peroxide which is a byproduct of the formation of oxyhaemoglobin in the lungs. The cell membrane becomes incompetent and sodium and water enters with resultant haemolysis. G6PD deficient red cells are more susceptible than normal red cells to oxidative damage. The reason for this is that NADPH, produced by G6PD, is required for regeneration of reduced glutathione (GSH) Dxidative damage can be caused by fava beans, infection and drugs Luzzato and Gardonsmith 1999).The ultimate effect of the disease is to produce anaemia either acute haemolytic or a chronic spherocytic type (Rebecca, 2001) The G6PD deficient state is frequently associated with neonatal hyperkernicterus and death (Beutler, 1994; Valees, 1994 and slusher et al, 1995). It is also the most important aetiological factor associated with neonatal jaundice in full term normal weight infants in Nigeria (Effong and Lehtan, 1995) and other parts of Africa (Nkrumah, 1978)G6PD deficiency in the most common enzyme deficiency status in the world with about 400 million people living with it, all races are affected and the highest prevalence is found among Africans, Asians and Meditarraneans (Carter and Gross 2002). The prevalence and pattern of G6PD deficiency in different haemoglobin types in Ile-Ife, Nigeria has been determined (Oduola and Olayink er al 2004) also reported demonstration of Heiz bodies for G6PD screening.The literature datas on stability of G6PD in whole blood stored with different anticoagulants tend to be contradictory; some authors advocate the use of ACD and glucose-EDTA while others said that ACD and glucose-EDTA do not sufficiently stabilize G6PD in whole blood. The same argument goes for other anticoagulants such as K2EDTA, citrate, oxalate, heparin, fluoride and CPD [12]. In many Nigerian hospital laboratories, including our own, G6PD screening is not carried out on overnight EDTA blood samples based on the fact that G6PD would have lost its activity. Since most of these