Monitoring human chorionic gonadotrophin level: evaluation of urine as an alternative specimen type

Although urine has been used widely for the qualitative detection of human chorionic gonadotrophin (hCG), serum is chosen conventionally for the serial quantification of the hormone to monitor trophoblastic activity. In response to requests from both clinicians and patients regarding the use of urine as an alternative specimen type, we designed this comparative study to evaluate the possibility, taking into account both laboratory technique and the distribution of hCG within different body fluids. Using the Access Chemiluminescent Immunoassay System, total beta-hCG was measured in serum and urine (n = 30) collected from patients hospitalised for first-trimester abnormal pregnancy. Results obtained with normalised urine (corrected with urinary creatinine) and serum total beta-hCG correlated well (r = 0.98, P < 0.001), and we concluded that urine could be used as an alternative specimen type for the serial quantitation of hCG to monitor trophoblastic activity. However, the assay used must detect the common beta 2 epitope.