Is it mandatory to examine synovial fluids promptly after arthrocentesis?
Arthritis Rheum 32:271-278, 1989 Fifty synovial fluid (SF) samples from patients with various types of arthritis were examined promptly after joint aspiration and after storage at room temperature (22 degrees C) or at refrigerator temperature (4 degrees C) for 1 hour, 2 hours, 3 hours, 6 hours, 1 day, and 3 days, then weekly for 3 weeks and monthly for 2 months. We found that the leukocyte count (white blood cell (WBC) count) decreased within a few hours. In 4 SF samples from patients with mild inflammation (initial range 3,1506,200 WBC/mm3), the WBC count decreased into a “non-inflammatory” range (less than 2,000/mm3) within 56 hours. In 3 of 5 SF samples that on the first day were found to be laden with crystals of calcium pyrophosphate dihydrate (CPPD), the crystals were much less abundant and were difficult to recognize by the next day. CPPD crystals dissolved completely in all SF samples by 38 weeks of the study. Monosodium urate crystals remained detectable throughout the 8 weeks
