BEDSIDE TESTING (SIMPLIRED) IN THE DIAGNOSIS OF DEEP-VEIN THROMBOSIS - EVALUATION OF 250 PATIENTS

RATIONALE AND OBJECTIVES. The authors evaluate the sensitivity and spe cificity of a bedside test (SimpliRED) in the diagnosis of deep vein t hrombosis compared with contrast phlebography. METHODS. Two hundred fi fty patients, referred for phlebography, underwent bedside testing for detection of deep vein thrombosis, Contrast phlebography was performe d immediately afterward. SimpliRED provides a clearly visible agglutin ation of the patient's red blood cells in the presence of elevated lev els of cross-linked fibrin derivative (D-dimer), which is specific for fibrin breakdown. RESULTS. In 82 (32.8%) patients, deep vein thrombos is was confirmed venographically. An abnormal D-dimer test was found i n 79 of the 82 patients with thrombosis (sensitivity: 96.3%), The thre e patients who were diagnosed falsely as normal on agglutinin testing, had venograms which showed only an isolated calf thrombosis in small muscle veins (<2 cm in diameter) not requiring treatment, One hundred of 168 patients without venographic thrombosis were diagnosed correctl y by SimpliRED (specificity: 59.5%). The positive predictive value was 53.7%; the negative predictive value was 96.8%. CONCLUSIONS. All thro mbotic disorders in the leg that required further treatment were ident ified correctly. SimpliRED is a very sensitive test with moderate spec ificity in the diagnosis of deep vein thrombosis. Therefore, further i nvasive testing is needed only in those patients in whom the D-dimer t est is abnormal. A false-positive result of the bedside test may be no nspecific or due to elevated levels of fibrin split products, which ca n occur whenever the coagulation system has been activated by any of s everal conditions.