An evaluation of the performance of laboratories in the assays of oestriol and creatinine in pregnancy urine: the national pregnancy urine survey.

The performance of clinical chemistry laboratories in New Zealand in the assays of oestriol and creatinine in pregnancy urine has been investigated. The quality of oestriol determinations in general was poor. Only seven of 20 laboratories achieved an inter-assay precision of better than 12 percent consistently through the range of oestriol levels represented by three control urines. The precision of laboratories in assaying urinary creatinine was, however, of a higher standard. Only three of 18 laboratories had precision values that could be regarded overall as unsatisfactory.