Assay of D-dimer based on immunofiltration and staining with gold colloids.
In this immunofiltration assay of D-dimer in plasma samples, the antigens are captured by a monoclonal antibody on a porous membrane, and labeled with the same antibody conjugated to gold colloids. The assay time is < 2 min, and a color of intensity proportional to the concentration of D-dimer is left on the membrane. The reference range (mean +/- 2 SD) was 0.336 +/- 0.133 mg/L (n = 69). Linearity was found up to 10 mg/L. Comparison with ELISA results (x) for 198 patients' samples demonstrated a linear regression equation of y = 0.99(+/- 0.05)x + 0.68(+/- 0.07) and a mean square error of 0.503. Comparison of visual reading of the color signal (y) vs reflectometric measurements (x) for 220 patients' samples demonstrated a linear regression equation of y = 2.5(+/- 0.06)x -0.22(+/- 0.04) and a mean square error of 0.095. Bilirubin, hemoglobin, fibrinogen, soluble fibrin, and fibrinogen degradation products and freezing/thawing of samples did not interfere. Some interference from rheumatoid factor, heparin, and the presence of cells or large lipid particles was seen. The variance (CV) was 8-12% within run, 10-18% between runs, and 13-20% between persons. The new assay constitutes a rapid and reliable analytical tool combining simplicity equivalent to that of latex tests with analytical information approaching that of ELISA.
Gogstad
G O
GO
Diagnostica R&D, Nycomed Pharma AS, Oslo, Norway.
Dale
S
S
Brosstad
F
F
Brandsnes
O
O
Holtlund
J
J
Mørk
E
E
Gärtner
E
E
Borch
S M
SM
D004355:Drug Stability; D004797:Enzyme-Linked Immunosorbent Assay; D005338:Fibrin Fibrinogen Degradation Products / Q000032:analysis*; D005374:Filtration; D005615:Freezing; D017979:Gold Colloid; D006358:Hot Temperature; D006801:Humans; D007118:Immunoassay / Q000379:methods* / Q000592:standards / Q000706:statistics & numerical data; D011786:Quality Control; D012680:Sensitivity and Specificity
D005338:Fibrin Fibrinogen Degradation Products; D017979:Gold Colloid; C036309:fibrin fragment D