212-POS

Abstract

Objectives Dipstick urinalysis is widely used for screening of proteinuria in pregnancy. Conflicting results have been reported for diagnostic accuracy between visual and automated methods. We compared semi-quantitative visual and automated dipstick methods with protein:creatinine ratio (PrCr, ⩾30 mg/mmol defined as elevated) in high risk pregnancy. Methods As part of routine clinical care, 517 random midstream urine samples were collected prospectively from consecutive outpatient ( N = 136) and inpatient ( N = 203) pregnant women attending high-risk maternity clinics. Samples were split into two aliquots. The first underwent point-of-care proteinuria testing using visual test strips (Multistix 10SG, Siemens Healthcare Diagnostics, Inc., Tarrytown NY). The second aliquot was sent to the hospital laboratory for analysis by each of two automated dipstick test strips (Multistix 10SG strip, Bayer Clinitek 50; Chemstrip®10 MD, and Urisys 1100®) and PrCr. For PrCr, urinary protein was measured by a pyrogallol red dye-binding method, and creatinine by an enzymatic method. For each of the dipstick methods, positive test thresholds (see Table) were used to determine diagnostic accuracy for PrCr ⩾ 30 mg/mmol. Results Included were 470 (91.7%) urine samples tested by all dipstick methods. The prevalence of proteinuria was low. All dipstick proteinuria methods showed low sensitivity and high specificity for detection of PrCr ⩾ 30 mg/mmol, although visual dipstick urinalysis had lower sensitivity than either automated method. For all dipstick methods, the positive likelihood ratio (LR) was good-excellent, but the negative LR was poor-fair. Conclusions Automated dipstick methods are more sensitive than visual urinalysis for detection of proteinuria, but diagnostic test performance is still poor-fair as a ‘rule-out’ test for proteinuria. Whether the enhanced sensitivity would be worth the cost and training is to be determined. Table 1 . AUC (area under the curve), CI (confidence interval), LR (likelihood ratio). Group 1 Visual Multistix 10SG strip Group 2 Automated Multistix 10 SG, Bayer Clinitek 50 Group 3 Automated Chemstrip® 10 MD, Urisys 1100® Positive test threshold +1 (0.3 g/l) +1 (0.3 g/l) +1 (0.25 g/l) Proteinuria present 36 (7.7%) 83 (17.7%) 59 (12.6%) Sensitivity (%, 95% CI) 50 (38–62) 71 (59–81) 63 (50–74) Specificity (%, 95% CI) 98 (97–99) 91 (87–93) 95 (93–97) Positive LR (95% CI) 40.8 (16.49–100.96) 7.42 (5.30–10.41) 12.83 (8.04–20.49) Negative LR (95% CI) 0.51 (0.40–0.65) 0.32 (0.22–0.47) 0.39 (0.28–0.54) AUC (95% CI) 0.74 (0.66–0.83) 0.81 (0.74–0.88) 0.79 (0.72–0.87) Disclosures M.E. Correa: None. A.C. Halstead: None. A. Cote: None. D.A. De Silva: None. L. Wang: None. P. von Dadelszen: None. L.A. Magee: None.