Okaka E .I, Oforofuo I.A.O. and Momoh S.M
Haemoglobin carbamylation occurs when isocyanate; a spontaneous breakdown product of urea reacts with the terminal valine residues of the α and β polypeptide chains of haemoglobin (Hb). Hb carbamylation depends on the duration of exposure t o high levels of urea. Carbamylated haemoglobin (CHB) is thus elevated in renal failure. The aim of this study was to develop a colorimetric method fo r the measurement of CHB in patients with renal failu re. Twenty patients with chronic kidney disease (CKD) and twenty persons with normal renal function were recruited in the study to determine their blood levels of CHB. CHB was measured using a color imetric method. Mean CHB levels were significantly higher in the CKD patients (107.5±16. 2) than in the normal controls (65±11.9); CHB expressed as microgram valine hydantoin per gram Hb (μgVH/gHb). There was significant correlation between CHB and urea, creatinine and Hb concentrati on, r=0.832, r=0.566 and r=-0.733 respectively. Following multiple regression analysis, urea was th e only predictor of CHB. At a CHB cut off level of 100μgVH/gHb, the sensitivity and specificity of thi s test to identify persons with CKD from those with normal renal function was 95% and 80% respectively. CHB levels can be determined with reasonable accuracy using a colorimetric method.
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