On admission, the results of a repeat aPTT test was 71.4 s (reference interval, 23-36 s), and factor VIII activity was markedly reduced in a chromogenic assay
(<10 IU/dL; reference interval, 50-175 IU/dL) and a clotting assay (<1 IU/dL; reference interval, 70-150 IU/dL).
Quantitative assessment of dabigatran levels can be obtained with the dilute thrombin time (dTT), the ecarin clotting time, or the ecarin chromogenic assay
. (16) Unfortunately, at present, these assays are not generally available and do not yet have FDA approval for measuring levels of dabigatran or other direct thrombin inhibitors.
The Olympus serum total bilirubin assay is an end-point chromogenic assay
(4) More recently, this disadvantage has been overcome by development of the ecarin chromogenic assay
(ECA) which has been described as a simple, rapid, precise, reliable, and specific method for the quantitative determination of DTIs.
The Roche total bilirubin assay is a liquid, end-point, chromogenic assay
based on a modification of the diazo method (10).
McGlasson DL: Using a single calibration curve with the anti-Xa chromogenic assay
for monitoring heparin anticoagulation.
This chromogenic assay
was initiated by dilution (1:25; 2 [micro]L + 48 [micro]L) of the plasma sample with antithrombin III/buffer concentrate and incubation for 160 s.
The iron in the ultrafiltrate was quantified by a chromogenic assay