A clinical comparative study on carbamylated haemoglobin as a surrogate marker to differentiate acute kidney injury from chronic kidney disease.

Introduction: Carbamylated haemoglobin is the result of reaction of isocyanate with N-terminal valine residues of the α and β chains of haemoglobin. Carbamylated haemoglobin concentration is dependent on the degree and duration of uraemia and thus may potentially serve as a marker to differentiate acute kidney injury (AKI) and chronic kidney disease (CKD).

Methods: A hospital-based prospective clinical comparative study was conducted in an urban tertiary medical care centre. Carbamylated haemoglobin was estimated in a total of 60 patients, 30 each of chronic kidney disease and acute kidney injury. The comparison of the carbamylated haemoglobin levels among the CKD and AKI groups was done using Mann-Whitney test. The mean value of carbamylated haemoglobin among the CKD group was 240.71 ± 75.64 μgVH/g, whereas among the AKI group, it was 67.15 ± 17.05 μgVH/g. These values are statistically significant with P < 0.001.

Results: Carbamylated haemoglobin values were elevated in relation to renal dysfunction, and it significantly correlated with chronicity of kidney disease. Mean CarHb among the CKD group was significantly high in comparison to the AKI group with statistical significance, with a P value of <0.001.

Conclusion: It was significantly attributed in this study that carbamylated haemoglobin >100 μgVH/g is diagnostic of CKD and a value <100 μgVH/g is diagnostic of AKI. Thus, in this study, it can be concluded that carbamylated haemoglobin is a useful marker to differentiate AKI from CKD.