Estimation of ionized calcium, total calcium and albumin corrected calcium for the diagnosis of hypercalcaemia of malignancy.

Objective: To measure levels of ionized calcium, total calcium and albumin corrected calcium in patients with different malignant disorders for the diagnosis of hypercalcaemia of malignancy. Design: A case control comparative study. Place and Duration of Study: The study was carried out in the Department of Pathology, Army Medical College Rawalpindi, Armed Forces Institute of Pathology and Department of Oncology CMH, Rawalpindi from March 2003 to December 2003. Subjects and Methods: Ninetyseven patients of various malignant disorders, admitted in the Department of Oncology, CMH, Rawalpindi, and 39 age and gender-matched disease-free persons (as control) were included in the study. Blood ionized calcium (Ca), pH, sodium (Na) and potassium (K) were analysed by Ion selective electrode (ISE) on Easylyte® auto analyser. Other related parameters were measured by colourimetric methods. Results: Blood Ca levels in patients suffering from malignant disorders were found significantly high (mean ± SD: 1.30+017 mmol/L) as compared to control subjects (mean ± SD: 1.23+0.03 mmol/L) (p<0.001). The number of patients with hypercalcaemia of malignancy detected by Ca estimation was significantly higher (38%) as compared to total calcium (8.4%) and albumin corrected calcium ACC (10.6%) (p<0.001). There was no statistically significant difference in other parameters e.g. phosphate, urea, creatinine, pH, Na and K levels in study subjects and controls. Conclusion: Detection of hypercalcaemia can be markedly improved if ionized calcium estimation is used in patients with malignant disorders.