Evaluation of sensitivity and specificity of six D-dimer latex assays

The results of six commercially available D-Dimer latex assays were compared with those obtained by two D-Dimer enzyme-linked immunosorbent assay; this comparison was done by assessing the sensitivity and specificity of the assays. Results indicated that five of the six latex assays were unable to detect consistently D-Dimer levels (ie, equal to the claims stated in the manufacturers' package inserts). Performance, in order of decreasing sensitivity ([true positive/(true positive+false negative)] as compared with the enzyme-linked immunosorbent assay results), was as follows: ACCUCLOT D-Dimer (Sigma Diagnostics, St Louis, Mo) (93.8%) greater than Fibrinosticon (Organon Teknika Corp, Durham, NC) (81.3%) greater than D-Di Test (Diagnostica Stago, Asnières, France) (68.8%) greater than Dade Dimer-test Latex Assay (Baxter Diagnostics Inc, Miami, Fla) (59.4%) greater than Dimertest Latex Kit (American Diagnostica Inc, Greenwich, Conn) and DimerKlone (Ortho Diagnostic Systems Inc, Raritan, NJ) (56.3%). The estimated sensitivity for the lowest sensitivity assays (group 1) (American Diagnostica Inc, Ortho Diagnostic Systems, and Dade Diagnostics) was approximately 1.5 mg/L; the estimated sensitivity for the moderate sensitivity assays (group 2) (Organon Teknika Corp and Diagnostica Stago) was approximately 1.0 mg/L; and the estimated sensitivity for the highest sensitivity assay (group 3) (Sigma Chemical Co) approached a detection limit in the 0.25- to 0.50-mg/L range.