The role of observer error in antenatal dipstick proteinuria analysis

Objective To determine the role of inter-observer error and the influence o f training upon dipstick urine analysis. Design A two phase observational and training study. Methods Five standard solutions of serum albumin were used to test the accu racy of midwives and nursing auxiliaries involved in dipstick urine analysi s at a maternity hospital. The standard solutions were chosen such that the y should have resulted in negative (n = 2) and positive (n = 3) dipstick te st results, respectively. Setting A teaching maternity hospital and academic department of obstetrics and gynaecology. Participants Twenty midwives, 20 nursing auxiliaries and nine laboratory te chnicians. Results For the two nonproteinuric solutions, a higher false positive rate was observed for nursing auxiliaries (40% and 55%), compared with midwives (5% and 30%) (P = 0.020 and P = 0.20, respectively). Before training, labor atory technicians recorded high false positive rates (67% and 89%), but aft er training these were reduced to 0% and 22% (P = 0.25 and P = 0.023, respe ctively). Both nursing auxiliaries and midwives recorded false negative rat es of between 10% and 45% for the three proteinuric solutions. Conclusions Observer error may be reduced by assigning midwives to urine di pstick analysis or by the implementation of directed training. Classificati on of pre-eclampsia or other hypertensive diseases of pregnancy on the basi s of the presence and degree of proteinuria should be confirmed with a 24-h our quantitative protein collection.