Saliva urea nitrogen dipstick – a novel bedside diagnostic tool for acute kidney injury

Abstract

SUN dipsticks allow the discrimination of AKIN 3 from earlier AKI stages. This low-technology approach may aid the screening of severe AKI in areas where laboratory resources are scarce.

Saliva Urea Nitrogen Continuously Reflects Blood Urea Nitrogen after Acute Kidney Injury Diagnosis and Management: Longitudinal Observational Data from a Collaborative, International, Prospective, Multicenter Study

“…This is also seen in the systemic bias as shown in figure 4 ; however, for the purpose of discrimination of levels indicating the presence of AKI at AKIN III, where BUN is higher, the underestimation appears not to affect diagnostic performance when using SUN. SUN in our data was consistent with the report of Calice-Silva et al [6] ; it was able to discriminate AKI at AKIN stage III vs. the less severe stages I and II, with a diagnostic performance comparable to BUN on every analyzed observation day ( fig. 5 and 6 ).…”

“…These analyses confirm our earlier reports on the agreement between SUN and BUN [5,6] and carry current knowledge on the diagnostic performance of SUN an additional step forward by analyzing the agreement and the diagnostic utility of SUN over a prolonged period of time (4 days) following first AKI diagnosis (as per the AKIN criteria [7] ). We have found that the agreement between BUN and SUN was comparable on all observation days, generally following a declining trend in BUN and creatinine ( fig.…”

“…Diagnostic performance of SUN and BUN to discriminate AKIN III vs. earlier stages was analyzed by predictive values (i.e. sensitivity and specificity after defining AKIN III as the binary outcome), and the area under the receiver operating characteristics curve at each of the 4 observation days following the approach defined by Calice-Silva et al [6] .…”

“…Evaluating the diagnostic performance of BUN and SUN, respectively, showed both parameters, applying the criteria of Calice-Silva et al [6] , enabling the discrimina- . 6 ).…”

“…We have conducted the current study and analyses as an advancement to our earlier studies, in which we have shown that saliva urea nitrogen (SUN) measured by a simple dipstick method reflects elevated blood urea nitrogen (BUN) in a cohort of patients with chronic kidney disease [5] , and permits the determination of AKI disease severity at hospital admission [6] . In this study, we have carried the analyses another step forward by investigating (a) the agreement between SUN and BUN and (b) the diagnostic performance of SUN to discriminate more advanced AKI from less severe cases longitudinally over a time period of up to 8 days.…”