A utilization review of theophylline assays: sampling patterns and use

Use of the theophylline assay was reviewed for two months in 121 hospital inpatients who received 426 evaluations at a university medical center. Clinicians adapted published audit criteria for the collection and use of theophylline assays. The charts of all patients receiving theophylline were examined daily, and the following data, among others, were collected: pulmonary function tests, arterial blood gases, liver function tests, vital signs, and physician assessments. Only 29.8 percent of the evaluations complied with all criteria. When the audit categories of rational indication, correct performance, and appropriate dosage adjustment were evaluated independently, compliance rates were 69.1, 72.3, and 67.2 percent, respectively. In 171 cases (48.6 percent), the physicians' instructions for the assay were inadequate to ensure proper collection time by the phlebotomist. Hospital laboratory charges for unnecessary, incorrectly performed, or inappropriately used theophylline assays were estimated to exceed +77000 annually. This audit demonstrates the need for a collaborative pharmacokinetics service with reimbursement through the physician billing charge.