Is point of care renal function testing reliable screening pre-IV contrast administration?

Intravenous iodinated contrast is a commonly used diagnostic aid to improve image quality on computed tomography. There exists a small risk of post-contrast acute kidney injury in patients receiving IV contrast. One of the biggest risk factors for developing PC-AKI is the presence of pre-existing renal dysfunction, making it important to measure the renal function prior to contrast administration. Point of care (POC) devices offer a quick estimation of renal function, potentially improving workflows in radiology departments.

Two POC devices were evaluated, the Nova StatSensor and Abbott iSTAT. Patients undergoing routine radiological investigations had blood collected and analysed by a POC method and the laboratory method (Beckman AU5800). The two values were analysed and compared. Renal function was calculated using eGFR via the CKD-EPI result. eGFR values were stratified as high risk (eGFR < 30), moderate risk (eGFR 30-59) and low risk (eGFR ≥ 60).

One hundred eighty-six patients were included in the study. One hundred one patients underwent the Abbott iSTAT analysis, 139 patients underwent Nova StatSensor analysis, and 53 had both. Statistical analysis revealed that the StatSensor R² value was 0.77, and coefficient variation was 10.65%. iSTAT had a R² value of 0.83 and coefficient variation of 7.36%. The POC devices did not miss any high-risk patients but underreported eGFR values in certain patients.

POC devices are moderately accurate at detecting renal impairment in patients undergoing radiological investigations. They seem to be a good screening tool; however, any low eGFR values should be further examined.