URINARY DIPSTICK PROTEIN - A POOR PREDICTOR OF ABSENT OR SEVERE PROTEINURIA

OBJECTIVE: Our purpose was to compare urinary protein dipstick Values with standard 24-hour urinary protein excretion in women with hyperten sion in pregnancy. STUDY DESIGN: Urinary protein dipstick determinatio ns and concurrent 24-hour urinary protein excretion measurements were compared by review of 300 urine samples obtained from women with hyper tension in pregnancy. RESULTS: One hundred twenty-three samples had ne gative to trace protein on dipstick on two occasions at least 6 hours apart. Eight-one (66%) of these patients had significant proteinuria ( greater than or equal to 300 mg per 24 hours). Seventy-six samples rev ealed 3+ to 4+ protein on dipstick in at least two samples. Of these, 27 (36%) had heavy proteinuria (greater than or equal to 5 gm per 24 h ours), and 42 (55%) had nephrotic range proteinuria of greater than or equal to 3.5 gm per 24 hours. One hundred one patients had urine dips tick values of 1+ to 2+, of whom 89 (88%) had significant proteinuria. CONCLUSION: Urinary protein dipstick values greater than or equal to 1+ have a positive predictive value of 92% (162/177) for predicting gr eater than or equal to 300 mg per 24 hours. In contrast, a dipstick of negative to trace should not be used to rule out significant proteinu ria because its negative predictive value is only 34% (42/123) in hype rtensive patients. Moreover, urine dipstick Values of 3+ to 4+ should not be used to diagnose severe preeclampsia because their positive pre dictive Value is only 36% (27/76).