This month's Kidney International features an interesting report by Vaidya et al which reports on the development of a potentially useful dipstick test able to detect urinary Kim-1, a promising new biomarker for acute kidney injury.
As we all know, the rise in creatinine is a relatively late event in AKI, and the field of nephrology would benefit from tests which detect renal injury at an earlier stage. In this paper, the investigators tested a dipstick test's ability to gauge Kim-1 levels in three different rodent models of acute kidney injury: cadmium toxicity, gentamicin toxicity, and ischemia-reperfusion injury. All three showed a reliable ability of the dipstick test to predict renal injury. An example of gentamicin-treated mice (compared to negative controls) is shown. There are two bands on the dipstick: an upper band (a positive control) and a lower band (Kim-1). You can see that in the urines of mice treatd with the higher concentration of gentamicin there is the appearance of a strong red/pink lower molecular weight band, indicative of elevated Kim-1 levels. The test was also shown to predict AKI in human patients undergoing cisplatin-chemotherapy regimens for mesothelioma. Obviously the characteristics of such a test in a larger population of hospitalized patients will have to be undertaken in a careful fashion before the Kim-1 test can be considered for more routine use, but I like the practical nature of such a test-- incorporation of such a test onto a dipstick sounds easy, and could someday become a routine useful tool for many inpatient nephrology consults.