Indigenous indicators of vitamin B12 deficiency

Abstract

Introduction: Clinical manifestations of vitamin B12 deficiency are mostly non-specific. An entity called subclinical deficiency has become popular where the need has arisen to perform costly investigations which indicate functional deficiency of vitamin B12 even when vitamin B12 levels are normal. These factors pose a challenge in planning management of patients. Aims and objectives : The study was conducted as an attempt to identify affordable and credible laboratory indicators of vitamin B12 deficiency which can be used as screening tests before choosing patients for further evaluation or treatment. Material and Methods : This was a time bound cross-sectional study where 100 adult patients who had undergone the following investigations were randomly chosen: Complete Blood Count with red cell indices, serum bilirubin and serum vitamin B12 levels. The sensitivity, specificity and predictive values (positive-PPV and negative-NPV) of the variables that could hypothetically identify vitamin B12 deficiency, both individually or in combinations were calculated and compared. Results and conclusion : Hemoglobin, MCV (Mean Corpuscular Volume), MCH (Mean Corpuscular Hemoglobin), platelets and bilirubin were not equally distributed between vitamin B12 deficient and normal groups(p values for these variables were 0.029, 0.000, 0.000, 0.003 and 0.029 respectively).When these variables were tested individually and in combination, the combination of [MCV=95 fl or MCH=30 pg or Platelets =1.4 lakh/µl or Bilirubin =1 mg/dl] had sensitivity of 68.2%, specificity of 85.7%, PPV of 78.9% and NPV of 77.4%. This proposed combination used as a screening test has potential for wide application considering its simplicity and cost advantage.

Keywords

• cobalamin deficiency
• erythrocyte indexes
• mean corpuscular hemoglobin
• mean corpuscular volume
• red cell indices