Diagnostic accuracy of semiquantitative point of care urine albumin to creatinine ratio and urine dipstick analysis in a primary care resource limited setting in South Africa

Abstract

Background The prevalence of chronic kidney disease (CKD) is predicted to rise over the next few decades. In resource-limited settings access to central laboratory services is limited. Point-of-care (POC) urine dipstick testing offers the potential to detect markers of kidney damage (albuminuria) as well as markers of other disease processes. We evaluated the diagnostic accuracy of the semi-quantitative albumin-creatinine ratio (ACR) Sysmex UC-1000 POC urine dipstick system as well as the extent of other abnormal dipstick findings in urine. Methods 700 participants from a rural area in South Africa were screened for albuminuria. A spot urine sample was used to measure POC and central laboratory ACR. We determined the sensitivity, specificity, positive predictive value and negative predictive value of the POC ACR, and recorded dipstick parameters. Results The prevalence of albuminuria was 11.6% (95%CI; 9.3–14.2). Those with albuminuria had higher mean diastolic (82 vs 79 mmHg, p = 0.019) and systolic (133 vs 128 mmHg, p = 0.002) blood pressures and a higher proportion of diabetes mellitus (17.6 vs 4.9%, p < 0.001). The sensitivity of the POC ACR system was 0.79, specificity 0.84, positive predictive value 0.39 and negative predictive value 0.97. The sensitivity improved to 0.80, 0.85, 0.85 and 0.89 in those with elevated blood pressure, diabetes mellitus, HIV positive status, and those 65 years and older, respectively. Abnormalities other than albuminuria were detected in 240 (34.3%) of the samples; 88 (12.6%) were positive for haematuria, 113 (16.1%) for leucocytes, 66 (9.4%) for nitrites and 27 (3.9%) for glycosuria. Conclusion Our study shows that POC ACR has good negative predictive value and could be used to rule out albuminuria when screening for CKD. Additionally, a high proportion of participants had other urine abnormalities detected with dipsticks which may reflect kidney disease or co-morbid untreated genitourinary pathology such as urinary tract infections or endemic schistosomiasis with important implications for CKD.

Performance evaluation of Hipee S2 point-of-care testing urine dipstick analyser: a cross-sectional study

“…Our study showed that the sensitivity of semiquantitative ACR to detect albuminuria was higher than specificity, and the NPV was higher than PPV. This was in keeping with other previous studies in that PPV ranged from 46% to 82%, while NPV was higher than PPV ranging from 71% to 99% in all studies 24–31. These findings suggest that a negative result measured by the POCT urinalysis device would be useful for excluding albuminuria, but any positive result would need to be confirmed with a quantitative ACR test.…”

Urine Dipstick Analysis on Automated Platforms: Is a Reliable Screening Tool for Proteinuria? An Experience from Umberto I Hospital in Rome

“…A total of 128 female patients (51.4%) and 121 male patients (48.6%) were included. This analysis, stratified for age and sex, represents a novelty with respect to previous studies [ 23 ].…”

“…Moreover, for the first time, to the best of our knowledge, we present a deep and accurate analysis of the results, having performed a sub-stratification based on age (including pediatric subjects) and sex of the enrolled individuals for each parameter. [ 23 ]. In the literature, numerous large-scale studies have tried to set up new protocols for the laboratory diagnosis of albuminuria, creatinuria, and ACR, according to the necessity of a new, faster, and less expensive method useful for large-scale screening of the general population [ 25 , 26 , 27 ].…”

Imported parasitosis as a diagnostic challenge in Primary Healthcare Clinic in the non-endemic region — a case study of schistosomiasis in English Division student

“…Amplification methods used in schistosomiasis diagnostics do not limit only to Sh-RPA, at present, they are under extensive research with promising results [18]. Furthermore, schistosomiasis remains a possible cause of isolated haematuria in its endemic regions [19].…”