Point-of-care measurement of serum creatinine in the intensive care unit.
OBJECTIVE
To test the precision and limits of agreement of point-of-care testing (POCT)-based measurement of serum creatinine (Cr) in critically ill patients.


METHODS
We studied 250 paired blood samples from 82 critically ill patients from a general intensive care unit by simultaneous POCT and central laboratory testing (Jaffé method). Correlation, precision, bias, and limits of agreement were assessed. Possible confounders for interference of noncreatinine chromogens were evaluated by multivariate linear regression analysis.


RESULTS
The mean difference in serum Cr measured by central laboratory and POCT was +9.6 μmol/L (95% limits of agreement: -11.2 to +30.4 μmol/L). The mean percentage difference between the two techniques was 8.7% (95% limits of agreement -7.8% to +25.1%). On multivariate regression, the difference in serum Cr was increased with greater hemoglobin and lactate levels but decreased with greater bilirubin, albumin, and calcium levels.


CONCLUSIONS
Compared with the central laboratory testing, POCT-based measurement of serum Cr in critically ill patients carried a small negative bias. This difference appeared affected by the blood levels of biochemical variables known to affect the Jaffé method. POCT-based Cr measurement appears sufficiently accurate for clinical use.
Department of Intensive Care, Austin Hospital, Heidelberg, Victoria, Australia.
Paolo
P
Calzavacca
Augustine
A
Tee
Elisa
E
Licari
Antoine Guillaume
AG
Schneider
Rinaldo
R
Bellomo
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003404:Creatinine / Q000097:blood*; D016638:Critical Illness; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D019095:Point-of-Care Systems; D011446:Prospective Studies; D015203:Reproducibility of Results; D055815:Young Adult
D003404:Creatinine