Painful joints. Clues to early diagnosis.

Many cases of joint pain may be diagnosed from clinical findings alone. A careful history and physical examination are essential. Of all diagnostic laboratory tests for joint disease, none is completely specific. Results of latex fixation tests, antinuclear antibody (ANA) tests, and uric acid tests are all strongly suggestive when positive but do not rule out disease when negative. The most valuable laboratory procedure is examination of the synovial fluid. X-ray examination seldom is helpful in differentiation of early joint disease but may be very helpful in later stages.