The RCPAQAP Synovial Fluid assesses the ability of laboratories to detect the key disease-related crystals (urate and calcium pyrophosphate) and to differentiate those from other crystalline structures such as corticosteroid, cholesterol and cartilage that may be found in synovial fluid. Through the use of capillary tips containing small amounts of synovial fluid, the same fluid sample can be distributed to all participating laboratories, allowing valid interlaboratory comparison. Participating laboratories can compare their own results with the group as a whole.
The examination of synovial fluid for crystals accounts for a very small part of laboratory workload but for the patient with possible crystal-induced arthritis the assessment of their synovial fluid is the key investigation which allows the establishment of a definitive diagnosis. The clinical scenario of a patient with joint pain and hyperuricaemia arises frequently. Most of these patients do not have gout, in fact only 20% of hyperuricaemic subjects (uric acid concentration above saturation, i.e. >0.42mmol/L) develop gout in their lifetime. An incorrect synovial fluid analysis report (particularly a false positive report of urate) could result in a recommendation for life-long drug therapy with little likelihood of the mistake being subsequently recognised. The aim of the RCPAQAP Synovial Fluid is to assist laboratories achieve and maintain an appropriate level of expertise in the assessment of synovial fluid. Laboratories participating in our programs receive samples and a DVD of microscopic examination of synovial fluid as survey materials. Participants also receive reports of their results and the same DVD with commentary. The DVDs allow exposure to uncommon crystal types; providing a teaching component to complement the quality assurance exercise. Participants receive notification of the accuracy of their results after results from all participants are evaluated.