Evaluation of rapid point-of-care creatinine testing in the radiology service of a large academic medical center: impact on clinical operations and patient disposition.

Background: Measurement of creatinine and calculation of the estimated glomerular filtration rate (eGFR) are widely employed to identify patients with chronic kidney disease who are at risk for contrast induced acute kidney injury and nephrogenic systemic fibrosis. However, patients may present for radiologic studies without a recent creatinine/eGFR necessitating cancelation of the study or performance of the scan without contrast. Both of these approaches are suboptimal.

Methods: We implemented a rapid whole blood point-of-care (POCT) creatinine test (iSTAT, Abbott Point-of-Care) in our radiology department and assessed the impact on clinical operations.

Results: Over a 7-month period a total of 3087 creatinine tests were performed. Overall 5.3% of patients presenting for scans (441/month) did not have a recent eGFR. An audit of 1 month of creatinine/eGFR values showed that 74% were normal permitting the scan to be performed without further consideration. Of the abnormal values 74% were performed with contrast and 26% without. Of note 78% of patients with an abnormal eGFR had a normal creatinine value. The cost of the POC test was $10.06 compared to a cost of $5.32 (including phlebotomy) for a creatinine performed in the central laboratory. The added incremental cost for the POC test was therefore $4.74.

Conclusions: Determining the cost effectiveness of the rapid test is extremely challenging because the analysis would need to take many complex factors into consideration including the effect on workflow in the radiology department, the clinical impact of more timely scans, the clinical and financial consequences of performing scans with or without contrast and the impact on revenues complicated by differential reimbursement rates and payor mix. However, given the benefits of the test on radiology operations and on the quality and timeliness of care it appears that the POCT test is cost effective and improves clinical operations.