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2nd Generation Cardiac Troponin Testing Introduced

Path Lab Offers New Cardiac Troponin Testing Beginning September 6

By Stuart Dubin, M.D., Ph.D., and Sergio Farber, Ph.D.

A decade of experience at Cedars-Sinai Medical Center has thoroughly validated the utility of Cardiac Troponin I (cTnI) as a sensitive, specific and highly useful marker of cardiac injury. Indeed, virtually all of the formerly employed assessments such as AST, LD, LD isoenzymes, CK, CK-MB and myoglobin have disappeared or are in the process of disappearing from the laboratory armamentarium of cardiac markers.

From the very beginning of its use, it became apparent that the unusually high specificity of cTnI suggested even low values of this marker might have clinical significance. Effective September 6, the Department of Pathology and Laboratory Medicine will replace its current assay with a second generation cTnI assay with an order of magnitude greater effective sensitivity and precision. Because of these enhancements, quite low values of the "Cardiac Troponin I Ultra" (cTnI Ultra) assay can be accurately measured, thereby revealing a level of cardiac injury possibly missed previously.

Consistent with the recommendations of the Joint European Society of Cardiology/American College of Cardiology and the World Health Organization, the CSMC Laboratory will post a new reference range for the "cTnI Ultra." Note that the decision thresholds are now lower than those previously employed:

< 0.05 ng/mLNegative.
Repeat testing in 4-6 hours if clinically indicated.
0.05 - 0.78 ng/mLSuspicious of myocardial injury.
Serial measurements may be required to confirm or exclude diagnosis of cardiac injury.
> 0.78 ng/mLConsistent with myocardial injury.
Repeat testing as clinically indicated.

Please direct any questions to Stuart Dubin, M.D., Ph.D., at (310) 423-5408 (dubin@cshs.org) or Sergio Farber, Ph.D., at (310) 423-5405 (farber@cshs.org).