OBJECTIVES: According to National Cholesterol Education Program-Adult Treatment Panel III, baseline lipid and lipoprotein measurements should be documented prior to initiating lipid-lowering therapy. This study describes the patterns of nonconformance to the measurement guideline, and assesses whether the nonconformance is associated with emergency department or hospital utilization. METHODS: Data were obtained from an administrative database of a managed care organization. The study sample consisted of all continuously eligible adult patients newly initiated with statins from June 1998-June 2000. All patients were followed for one year. Patients without lipid or lipoprotein measurement within six months prior to or on initiation date were identified as nonconforming. CPT codes were used to identify lipid/lipoprotein measurements. Cox proportional hazard regression evaluated the impact of laboratory nonconformance to time to the first emergency department or hospital utilization. Logistic regression was performed to assess the risk factors for nonconformance. RESULTS: Among 25,854 selected patients, 10,205 (39.5%) patients have any claim record for lipid/lipoprotein measurement before initiation of statin therapy. After controlling for 38 covariates including patient demographics, payer type, physician specialty, previous drug, and medical utilization pattern, and comorbidities, patients with nonconformance have 9.2% higher likelihood of earlier emergency department or hospital utilization conforming patients (p=0.006). Logistic regression revealed that older age, HMO in contrast to PPO are risk factors of nonconformance, while prescribing physician specialty (cardiology or internal medicine), previous use of Niacin, and patients with comorbidities are more likely to receive baseline measurement. CONCLUSIONS: The use of administrative claims to determine conformance with ATP III on lipid/lipoprotein measurement is subject to reporting limitations, but it appears that recorded rate of conformance to the guideline recommendation is low. Nonconformance to the guideline recommendation is significantly associated with emergency department or hospital utilization.