Submit Manuscript | http://medcraveonline.com Abbreviations: COMP, cartilage oligomeric matrix protein; HA, hyaluronic acid; OA, osteoarthritis; KOA, knee osteoarthritis; ELISA, enzyme linked immuno-sorbent assay; ROC, receiver operator curve; SPSS: statistical package for social sciences Introduction Osteoarthritis (OA), leads to considerable morbidity and disability in elderly. 1 The condition is diagnosed basically on clinical presentation and radiographic fndings. By the time changes are visible on radiographs the disease is fairly advanced. Radiographic changes are apparent only after a year or two, but changes in biomarker levels are apparent within a few months. 2 Biomarkers are used to diagnose the condition in early stage, to assess the disease progression and effcacy of treatment. Serum cartilage oligomeric matrix protein (COMP) and serum Hyaluronic acid (HA) are the two diagnostic biomarkers which are most often used. 3,4 Only few studies are found in literature of comparing the sensitivity and specifcity of COMP and HA. The aim of this study is to assess the role of COMP (biochemical marker for cartilage degradation) and HA (biochemical marker for synovial infammation) in early diagnosis of knee osteoarthritis (KOA). Materials and methods The study was conducted in the out-patient department of a tertiary care centre during a period of 2 years. Clearance from ethical and research committee of the institution was taken. An Informed and written consent was taken from all those included in the study. Patients aged 40 years or more reporting to us with complaints of non-traumatic knee pain ftting into the clinical criteria of American college of rheumatology were included in this study. All those with a. Secondary osteoarthritis, b. Current medications for treatment of osteoarthritis, c. Hepatic, renal and malignant disease, d. Any other disease affecting knee joint, e. Lactating/pregnant females, f. Involvement in heavy physical activity, g. Substance abuse was excluded from the study. Controls were selected from, preferably, the frst degree relatives of the cases with no signs and symptoms of knee osteoarthritis and above 40 years of age. All subjects were asked to fll the WOMAC questionnaire and were subjected to weight bearing knee radiography. The blood samples were tested for serum levels of Hyaluronic acid (HA) and MOJ Orthop Rheumatol. 2015;2(2):78‒82. 78 © 2015 Singh et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and build upon your work non-commercially. Cartilage oligomeric matrix protein (COMP) and hyaluronic acid (HA): diagnostic biomarkers of knee osteoarthritis Special Issue - 2015 Sudhir Singh, 1 Dharmendra Kumar, 2 Sanjiv Kumar, 1 Nishant Raj Sharma 1 1 Department of Orthopaedics, Era’s Lucknow Medical College, India 2 King George’s Medical University, India Correspondence: Sudhir Singh, Head - Department of Orthopaedics, Era’s lucknow medical college, Lucknow, India, Tel -8799544814, Email Received: February 18, 2015 | Published: March 14, 2015 Abstract Introduction: Osteoarthritis of knee is diagnosed on clinical features, functional and radiological evaluation. More recently biochemical markers are used to diagnose the condition in early stage, to assess the disease progression and effcacy of treatment. Aims & Objectives: The aim of the study is to assess role of serum Cartilage oligomeric matrix protein (COMP) and serum Hyaluronic acid (HA) levels as diagnostic biomarker and burden of disease biomarker in primary knee osteoarthritis. Materials and Methods: Radiographic assessment (K-L grading) and functional assessment (WOMAC score) was done for 100 cases and 50 control subjects. Serum COMP and HA levels were estimated for all the subjects. Results: Mean HA levels in mild cases was 14.07+7.04 ng/ml, in moderate cases was 38.28±41.34 ng/ml and in severe cases was 148.41+133.06 ng/ml (p<0.001). Mean COMP levels in mild cases was 606.08 ±105.27 ng/dl, in moderate cases it was 702.44±133.16 ng/dl and in severe cases it was 898.24 ±82.09 ng/dl (p<0.001). HA levels show good discriminant ability of between cases and control (sensitivity: 95.0%, specifcity: 90.0%), between mild and moderate case (sensitivity: 87.6%, specifcity: 86.0%) and between moderate and severe cases (sensitivity: 92.3 %, specifcity: 93.1%). COMP show excellent discriminant ability between cases and controls (sensitivity: 98%, specifcity: 98.0%), between mild and moderate cases (sensitivity: 92.9%, specifcity: 93.2%) and in between moderate and severe cases (sensitivity: 100%, specifcity: 97.7 %). COMP estimation shows higher sensitivity, specifcity and accuracy as compared to HA as diagnostic and burden of disease biomarker. Conclusion: COMP estimation shows higher sensitivity, specifcity and accuracy as compared to HA as diagnostic and burden of disease biomarker. Keywords: biomarkers, osteoarthritis, COMP, HA, KOA MOJ Orthopedics & Rheumatology Research Article Open Access