OBJECTIVES: Quality improvement initiatives in acute coronary syndrome (ACS) such as CRUSADE have found marked increase in treatment guideline adherence during the past several years. This descriptive study used time-stamped data to examine pharmacologic treatment and laboratory biomarker utilization patterns in ACS patients who underwent percutaneous coronary intervention (PCI). METHODS: The data source consisted of 19 hospitals throughout the U.S. that used time-stamp data from January 2003-September 2004. ACS was identified in the dataset using ICD-9 diagnosis codes for unstable angina and/or myocardial infarction (MI). The time-stamp allowed more precise measurement of drug administration and biomarker sampling. Biomarker definition of MI was CK-MB >3 times upper limit of normal, troponin I and myoglobin > 1 times upper limit of normal. RESULTS: A total of 6,282 ACS patients who had been given clopidogrel were identified with adequate time-stamp information. The most common recorded comorbid diagnoses were ischemic heart disease 91.2%, hypertension 54.4%, lipid disorder 57.9%, and diabetes 21.7%. Aspirin (ASA) plus clopidogrel was received by 75.9% of patients and initiated on the day of PCI in 88.3% of patients. The majority of initial ASA plus clopidogrel administration was minus (-)10 to plus (+)14 hours from PCI. GPIIb/IIIa inhibitors were received by 68.6% and statins by 73% of patients, respectively during hospitalization. Post-procedure (>8 hours after PCI) biomarker monitoring (CK-MB, troponin I or myoglobin) was performed in 67.9% of patients. The majority of testing was CK-MB or troponin I. Results suggestive of MI were found in up to 67% of patients. CONCLUSIONS: This novel examination of ACS treatment using time-stamped data found ASA, clopidogrel, GPIIb/IIIa inhibitors and statins were often used in this cohort. A wide range of initial administration time for ASA plus clopidogrel around PCI was found. Post-procedure biomarker monitoring occurred frequently and was often positive.