Screening and Assessment of Bone Health in Indian Women Using an Indigenous ELISA of Human Osteocalcin a Bone Turnover Marker

Osteoporosis a major public health problem of the elderly, is associated with substantial morbidity and socio economic burden. The aim of the study was to screen women with low bone mass using the indigenously developed Osteocalcin (OC) ELISA kit and compare it with commercial ELISA kit and evaluate. The diagnostic potential of the assay was assessed in 359 samples from neighboring tertiary care hospitals over a period of 2 years. OC levels were estimated by the developed indigenous assay in samples, correlated with the Bone Mineral Density (BMD) measurements and compared by a commercial ELISA kit. On the basis of T-scores the women were stratified into Normal and case groups as Osteopenia and Osteoporosis. The serum biochemical parameters calcium and phosphorus were estimated on an auto-analyzer. To compare two different assays Bland-Altman plot and Deming linear regression analysis was performed. The prevalence of Osteopenia was high (56%) and Osteoporosis (13%) in the healthy Indian women aged 21-65 years with significant differences in OC levels in normal and women with low bone mass. Good correlation (p < 0.0001) in the OC levels by the two assays was observed. Cut off limits established earlier with indigenous assay (11.9 ng/mL and 14.9 ng/mL) for Osteopenia and Osteoporosis were similar to those with the commercial kit (13.2 ng/mL and 16.8 ng/mL) respectively. The diagnostic sensitivity, specificity and accuracy of the OC prototype was > 85%. The cost effective OC prototype can be used in screening and management of Indian women with low bone mass.