Estimated reference interval of ionized [free] calcium

To determine the reference values of Ca++ in whole blood in our setup. The Department of Chemical Pathology and Endocrinology, Armed Forces Institute of Pathology, Rawalpindi from Jan 2008 to June 2008. Three hundred healthy individuals were included in the study after obtaining written consent. Out of these 76 individuals were excluded from the study after clinical assessment and collection of laboratory data. One hundred and fourteen were males with mean age 35 +/- 12 years and 110 were females, with mean age 28 +/- 9 years of age. Their Ca++ was estimated by ion selective electrode [ISE] method in heparinized whole blood [WB]. The mean and SD of whole blood Ca++ was calculated separately for the females and the males. The results showed that in our setup males have Ca++ levels of 1.12 +/- 0.05 [mean +/- SD] mmol/l and females have Ca++ levels of 1.12 +/- 0.04 [mean +/- SD] mmol/l. The study revealed that estimated reference range of Ca++ of the studied population was lower than the reference range published for the western population that is used by our physicians for the interpretation and comparison of results

Comparison of low dose short synacthen test [1 microgram] with standard dose short synacthen test [250 microgram] in patients of adrenal insufficiency

To determine the diagnostic accuracy of low dose 1 microg short synacthen test taking standard dose 250 microg short synacthen test as gold standard. A descriptive study. Department of Chemical Pathology and Endocrinology Armed Forces Institute of Pathology Rawalpindi from Jan 2006 to Jan 2007. Thirty patients with clinical suspicion of adrenal insufficiency and equal number of age matched healthy males and females as controls were included in the study. Relevant clinical history and physical examination was recorded on designated proforma. Short synacthen test was performed between 0800 - 1000 h by using ACTH doses of 1 microg and 250 microg with interval of 3 days in all patients and controls. Three blood samples were obtained for cortisol [basal, 30 min and 60 min after l/M ACTH injection]. Using 250 microg short synacthen test as a standard test, the 1 microg short synacthen test had sensitivity of 100%, specificity of 72%, positive predictive value of 71% and negative predictive value of 100% and 83% accuracy. The low dose 1 microg short synacthen test is as sensitive as standard dose 250 microg short synacthen test but less specific in the diagnosis of adrenal insufficiency