a serologic screening method used as an aid in the diagnosis of syphilis; after only a few drops of heparinized blood (obtained from a pricked finger) are collected in a special capillary tube, the capillary tube is centrifuged in order to collect plasma, which is then mixed with a 0.01-mL drop of antigen (cardiolipin previously treated with choline chloride as an antiinhibitor, to avoid falsely negative results that may occur with nonheated plasma or serum). After mechanically agitating the antigen-plasma mixture for 4 minutes, the presence or absence of flocculation is observed. A positive result should not be regarded as conclusively diagnostic, but a negative result excludes the likelihood of syphilis.
plasmacrit testAn obsolete serologic screening method for syphilis that utilised heparinised capillary tubes to enhance the sensitivity of cardiolipin-type tests.
plas·ma·crit test(plaz'mă-krit test)
A serologic screening method for syphilis; heparinized blood is centrifuged in a capillary tube and the plasma thus separated is combined with cardiolipin antigen. The presence of flocculation should not be regarded as conclusively diagnostic, but a negative result excludes the likelihood of syphilis. Considered obsolete in some parts of the U.S.