A point-of-care device for acute kidney injury: a fantastic, futuristic, or frivolous 'measure'?

This Commentary discusses concepts related to the development of the point-of-care (POC) diagnostic system and its advantages and disadvantages. Also discussed are the patient, provider, and financial outcomes that ought to be evaluated before the POC test becomes available for clinical use.

Point-of-care (POC) testing is diagnostic testing performed outside of a central laboratory at the site of patient care, such as a hospital, an emergency room, a physician's office, or at home. The primary advantage of a POC test is its ability to provide rapid test results and, thus, facilitate earlier treatment. Other advantages include the avoidance of specimen processing and smaller volumes of specimen needed for testing. Because of the convenience of POC testing, the menu of analytes available for testing is increasing rapidly, and POC testing is believed to represent 25% of the total expenditures of laboratory testing dollars. At present, more than 40 laboratory clinical analytes are available with the POC testing method. Although POC testing is a relatively new paradigm in laboratory analysis, nephrologists have been familiar with this concept for several decades. One of the oldest tests available by POC testing is the dipstick for urinalysis, which is routinely performed in the office setting. In addition, the popularity of the home pregnancy test is good evidence that POC testing is accepted and favored by the public.

Vaidya and colleagues (this issue) describe a study in which they developed a rapid and sensitive detection system (the RenaStick) for urinary kidney injury molecule-1 (KIM-1) and evaluated this system in animal models of acute kidney injury (AKI). The results demonstrate the multiple advantages of this technique over currently available laboratory methods for detection of KIM-1 as a biomarker for AKI. These include greater ease of use, visual readout, high sensitivity, and rapid detection. The authors have validated the technique in various rodent models of AKI (for example, cadmium toxicity, gentamicin toxicity, and ischemia/reperfusion). In the preclinical models, the results were correlated with renal histology, KIM-1 staining, and the microbead-based KIM-1 assay. Some limitations of RenaStick were addressed, such as its inability to measure absolute values. RenaStick was also tested in a small number of human urine samples and appears to work well for extremes of KIM-1 values. Further testing and validation of RenaStick in a large cohort of human samples and using Standards for Reporting of Diagnostic Accuracy (STARD) criteria will be important for demonstrating the utility of RenaStick for clinical use.

Full commentary article can be read at :

Parikh CR, A point-of-care device for acute kidney injury: a fantastic, futuristic, or frivolous 'measure'? Kidney Int. 2009 Jul; 76 (1): 8-10.  

http://www.nature.com/ki/journal/v76/n1/full/ki2009125a.html