Long-term experience with an accelerated protocol for diagnosis of chest pain.

CONTEXT: More than 6 million patients present annually with chest pain suggestive of acute coronary syndrome. Rapid and accurate diagnosis is essential for best clinical outcomes, for optimal management of hospital resources, and for minimizing medicolegal exposure. OBJECTIVE: To evaluate the clinical and cost outcomes of an accelerated protocol for chest pain triage in a community-based hospital of moderate size. METHODS: One hundred successive patients with chest pain were diagnosed according to the Traditional Chest Pain Protocol, which included testing of serial blood samples for creatine kinase (CK)-MB and total CK. These patients were also subjected to the Accelerated Chest Pain Protocol under evaluation, which included testing at shortened intervals for myoglobin and cardiac troponin I in addition to CK and CK-MB. Diagnostic sensitivity and specificity were compared versus the final assigned diagnosis. The Accelerated Chest Pain Protocol was implemented for routine use. Follow-up evaluations were conducted at 1 month (test group A, N = 180) and 22 months (test group B, N = 180). Costs for diagnosis and treatment of the 2 test groups were compared with those for the control group. RESULTS: The 2 protocols had equivalent specificity values (99%). The sensitivity of the Accelerated Chest Pain Protocol was higher than that of the Traditional Chest Pain Protocol (95% vs 58%). Cost savings of 29% and a reduction in length of stay of 33% were achieved in test group B versus the control group. CONCLUSIONS: The Accelerated Chest Pain Protocol improved the accuracy and timeliness of diagnosis of acute coronary syndrome while reducing costs.

An evaluation of ethylene glycol-based liquid specimens for use in quality control.

We investigated the analytical acceptability of ethylene glycol-based control sera by preparing sets of aqueous and ethylene glycol-based specimens that had added uric acid, calcium, creatinine, glucose, urea, sodium, and potassium. Ethylene glycol caused a significant systematic proportional bias in procedures involving dialysis, but had no discernible effect on methods not involving dialysis. The extent of bias was proportional to the concentration of ethylene glycol, was independent of protein concentration, and differed according to the type of dialysis system used. We conclude that ethylene glycol-based control materials can have useful applications in clinical chemistry, but caution must be exercised in their use with analytical systems that employ dialysis.

Performance evaluation of multi-channel analyzers by use of linearly-related survey specimens.

Sets of specimens having quantitative linear inter-relationships for 25 analytes were prepared and used in a small survey of results with multi-channel analyzers. Instrument calibration was evaluated by linear regression analysis of the analytical results, with calculation of the x- and y-intercepts and slopes. The average intercepts and slopes agreed quite well with those expected on the basis of specimen preparation, but the results from individual laboratories and from particular kinds of instruments demonstrated a variety of analytical biases. We conclude that performance of multi-channel analyzers can be evaluated effectively by such use of linearly related specimens in an inter-laboratory survey.

Design of quality-control specimens for use with a small multi-channel analyzer.

Specimens having linear relationships between concentration and instrument response for seven analytes were prepared for use with a small multi-channel analyzer. The specimens had inter-specimen and inter-constituent relationships that facilitated the performance evaluation of all channels simultaneously with each individual specimen. Techniques are described for use of the specimens in various aspects of quality control.