The role of observer error in antenatal dipstick proteinuria analysis

Objective To determine the role of inter–observer error and the influence of 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 accuracy of midwives and nursing auxiliaries involved in dipstick urine analysis at a maternity hospital. The standard solutions were chosen such that they should have resulted in negative (n= 2) and positive (n= 3) dipstick test results, respectively. Setting A teaching maternity hospital and academic department of obstetrics and gynaecology. Participants Twenty midwives, 20 nursing auxiliaries and nine laboratory technicians. 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, laboratory technicians recorded high false positive rates (67% and 89%), but after training these were reduced to 0% and 22% (P= 0.25 and P= 0.023, respectively). Both nursing auxiliaries and midwives recorded false negative rates of between 10% and 45% for the three proteinuric solutions. Conclusions Observer error may be reduced by assigning midwives to urine dipstick analysis or by the implementation of directed training. Classification of pre‐eclampsia or other hypertensive diseases of pregnancy on the basis of the presence and degree of proteinuria should be confirmed with a 24–hour quantitative protein collection.