1. RELATIONSHIP BETWEEN PARATHYROID HORMONE, VITAMIN-D, CALCIUM AND PHOSPHORUS IN CKD Neeraja Kunireddy, Priscilla Abraham Chandran, Sree Bhushan Raju, M.Noorjahan. DEPARTMENT OF BIOCHEMISTRY NIZAM’S INSTITUTE OF MEDICAL SCIENCES, HYDERABAD. Introduction  Chronic kidney disease -mineral bone disorders (CKD-MBD) is defined as a systemic disorder of mineral and bone metabolism associated with abnormalities of calcium, phosphorus, PTH or vitamin D metabolism.  Secondary hyperparathyroidism(SHPT) is an overproduction of PTH caused by several changes that occur in bone and mineral metabolism as a result of decreased kidney function.  In addition to bone mineral defects and disease, alterations in calcium, phosphorus, vitamin D, and PTH cause other deleterious consequences primarily cardiovascular calcification and is directly correlated to increase in morbidity and mortality.  Identifying patients at risk and evaluating for SHPT is important because early intervention slows or arrests the progression of bone and cardiac disease in CKD patients. Aims & Objectives  The aim is to evaluate the relationship between bone markers (iPTH, vitamin-D, calcium and phosphorus) in various stages of CKD. Materials & Methods  A total of 123 CKD patients which are divided into stage III (n=19), stage IV ( n=27), stage V( n=77) are included in the study.  They are classified in to three groups based on eGFR.  eGFR calculated by MDRD 6-variable equation. GFR (mL/min/1.73 m 2 ) = 170X(S.Cr / 88.4) - 0.999 X age - 0.176 X (SU X 2.78) - 0.17 X albumin 0.318 X (0.762,if F) (1.18, if African American).  Serum urea, creatinine, albumin, iPTH, 25(OH) D 3, calcium and phosphorus were estimated.  Serum creatinine was estimated by Jaffe’s kinetic method (traceble to IDMS) on Siemens Dade Dimension analyzer.  Serum urea was estimated by enzymatic kinetic UV assay.  Calcium, phosphorus was estimated by Colorimetric assay with endpoint determination.  iPTH, VITAMIN-D were determined by ELECTROCHEMILUMNICENT IMMUNOASSAY.  Pearson’s correlation and ANOVA test are used to assess the relation between the parameters. Results Mean±SD values of various parameters in different stages of CKD are:  Statistical significant difference is found with iPTH and phosphorus among different stages of CKD. Statistically significant negative correlation was found between iPTH and eGFR, phosphorus and eGFR. Discussion  CKD-MBD refers to the changes in bone, and it is a multifactorial disorder resulting from abnormalities in mineral metabolism, includes vitamin and calcitriol deficiency, hyperparathyroidism, disordered phosphate and calcium metabolism,and elevated fibroblastic growth factor 23 (FGF23)(1).  PTH is the most important regulator of calcium metabolism. Hyperparathyroidism that develops relatively early in CKD is the major driving force in the development of osteitis fibrosa(1).  In our study, Serum phosphorus showed a statistically significant correlation with eGFR.  When GFR falls, the phosphorus clearance decreases significantly, leading to phosphorus retention(2). Conclusions Our study shows importance of the determination of iPTH and phosphorus for early detection of SHPT. iPTH level are increased earlier than other bone markers. Early screening of CKD patients with serum iPTH levels helps in early detection and intervention of SHPT which reduces considerable mortality and morbidity. References 1.Study of possible correlation between inflammation and bone mineral disorders in Chronic Kidney Disease.Said S.Khamis1,Hany S. Elbarbary1,Mahmoud M. Emara1, Enas S. Essa2 and Ahmed A.Zayed1 International Journal of Recent Scientific Research, July, 2014. 2. Relationship Between Serum Parathyroid Hormone Levels, Vitamin D Sufficiency, and Calcium Intake. Laufey Steingrimsdottir, PhD Orvar Gunnarsson, MD Olafur S. Indridason, MD, MHS Leifur Franzson, MSc, Pharm Gunnar Sigurdsson, MD, PhD. JAMA. 2005 REG No:14370