Related Experiment Videos
Fluid therapy directly interferes with immunoassay for cardiac troponin I
F Lagneau1, P Beyne, P Letteron
1Service d' Anesthésie-Réanimation, Hôpital Beaujon, Clichy, France. jean.marty@bjn.ap-hop-paris.fr
Objective:
To investigate interference in cardiac troponin I (cTNI) immunoassay induced by some widely used loading fluids.
Setting:
A biochemistry unit of a university hospital.
Measurements And Results:
Human serum with a cTNI concentration of 0.32 microg/l was diluted at 10, 20, 40, and 80% with saline serum (SS), Plasmion (P) (a modified fluid gelatin), hydroxyethyl starch (HES), and 20% human albumin (Alb). Serum with a cTNI concentration of 1.29 microg/l was diluted at 20, 40, 60, and 80%. Four samples with increasing cTNI concentrations (from 0 to 8.14 microg/l) were diluted at 80% with the four fluids. Differences (delta-C) between expected concentrations resulting from the dilutional effect and those measured with the Access cTNI immunoassay were expressed in microg/l. Statistical analysis was performed using a nonparametric test. No false positivity was observed. At a low cTNI concentration (0.32 microg/l), interference was observed with SS and HES at 40 and 80% dilution and with P and Alb at 80%. When cTNI was 1.29 microg/l, interference was observed with each fluid at a dilution of 20% and increased with the increase in dilution. The highest interference was observed with HES, the lowest with P. When the dilution was at 80% for increasing concentrations of cTNI, the higher the initial cTNI was the higher the interference appeared, mostly with SS and HES.
Conclusions:
SS, P, Alb, and HES interfere in this cTNI immunoassay. This interference is higher with SS and HES and is higher when the percentage of hemodilution or real cTNI concentration increases.