Uses and misuses of serum hCG--a clinical audit

A 24-hour laboratory-based service was established in the City Hospital, Birmingham, England, in 1987 for semi-quantitative serum human chorionic gonadotrophin (hCG) assay and specific clinical criteria for requests were agreed. However, a 309% increase in workload between 1988 and 1992 prompted a detailed clinical audit of this service. During a representative month only 35% of 142 requests conformed to the agreed criteria. Those for routine diagnosis of pregnancy, threatened miscarriage, and 'abdominal pain screen' comprised 49% of total requests and seemed inappropriate. No pregnancy was diagnosed by 'abdominal pain screen'. Adhering to agreed clinical criteria, therefore, would not jeopardise patient care and could halve the cost of the service. As a result of this audit the established criteria for serum hCG estimation were reinforced and re-issued to all relevant clinical teams. Additionally, to improve delivery of service and reduce costs a semi-quantitative urine hCG assay was introduced in the Accident and Emergency Department for use by approved staff. Records in this department showed no increase in hCG requests during the six months after the service change, compared with those in the preceding half year. However, theoretical cost savings of 5173 pounds per annum were eroded by an estimated 10% because 208 (26%) tests were unaccounted for. The reasons for this apparent 'wastage' are unclear, and highlight the difficulty in auditing a biochemical test performed outside the laboratory.