Point-of-care creatinine testing for kidney function measurement prior to contrast-enhanced diagnostic imaging: evaluation of the performance of three systems for clinical utility.

BACKGROUND: Acute kidney injury (AKI) can occur rarely in patients exposed to iodinated contrast and result in contrast-induced AKI (CI-AKI). A key risk factor is the presence of preexisting chronic kidney disease (CKD); therefore, it is important to assess patient risk and obtain kidney function measurement prior to administration. Point-of-care (PoC) testing provides an alternative strategy but there remains uncertainty, with respect to diagnostic accuracy and clinical utility.

METHODS: A device study compared three PoC analysers (Nova StatSensor, Abbott i-STAT and Radiometer ABL800 FLEX) with a reference laboratory standard (Roche Cobas 8000 series, enzymatic creatinine). Three hundred adult patients attending a UK hospital phlebotomy department were recruited to have additional blood samples for analysis on the PoC devices.

RESULTS: The ABL800 FLEX had the strongest concordance with laboratory measured serum creatinine (mean bias=-0.86, 95% limits of agreement=-9.6 to 7.9) followed by the i-STAT (average bias=3.88, 95% limits of agreement=-8.8 to 16.6) and StatSensor (average bias=3.56, 95% limits of agreement=-27.7 to 34.8). In risk classification, the ABL800 FLEX and i-STAT identified all patients with an eGFR≤30, whereas the StatSensor resulted in a small number of missed high-risk cases (n=4/13) and also operated outside of the established performance goals.

CONCLUSIONS: The screening of patients at risk of CI-AKI may be feasible with PoC technology. However, in this study, it was identified that the analyser concordance with the laboratory reference varies. It is proposed that further research exploring PoC implementation in imaging department pathways is needed.