IMPORTANT Test and Policy Updates

Valued WestPac Labs Client and Care Provider,

5th Generation Troponin T Test (Test Code C175)

WestPac Labs is pleased to announce the conversion of troponin testing from the current troponin T assay to the enhanced generation 5 cardiac troponin T (Roche, cTnT GEN5) for the comprehensive evaluation of AMI. The new assay is a high-sensitivity cardiac troponin that enables more sensitive and precise detection at low troponin concentrations.

Troponin T (TnT) is a component of the contractile apparatus of the striated musculature. Although the function of TnT is the same in all striated muscles, the cardiac isoform of TnT originating exclusively from the myocardium (cardiac TnT, molecular weight 39.7 kDa) clearly differs from skeletal muscle TnT. As a result of its high tissue-specificity, cardiac troponin T (cTnT) is a cardio-specific, highly sensitive marker for myocardial damage.

Rapid, precise, and accurate detection of clinical, imaging, electrophysiological, and biomarker findings are the foundation for the diagnosis of acute myocardial infarction (AMI). Although current cardiac-specific assays are effective, they are often limited by decreased sensitivity and impression.

The Universal Definition of Myocardial Infarction (UDMI) recommends as an “optimal precision” the coefficient of variation (CV) at the 99th percentile upper reference limit to be less than 10%. The Roche Generation 5 Cardiac Troponin T meets the UDMI criteria for “guideline acceptable” precision and the International Federation of Clinical Chemistry (IFCC) definition of a high sensitivity assay.

Important points:

Units of Measure: Results are currently reported in ug/L. The new troponin 5th generation will be reported in ng/L.
Sex-Specific Reference Ranges: < 14 ng/L for females, < 22 ng/L for males, and < 19 ng/L for not specified.
Critical Value Has Changed: The new critical value for the 5th generation troponin assay will be greater than or equal to 14 ng/L for Females, greater than or equal to 22 ng/L for Males, and greater than or equal to 19 ng/L for not specified.
Only Li-Heparin Plasma Specimens: Test is not FDA approved on serum. Serum specimens will be rejected.

HIV DUO

WestPac Lab has replaced the “HIV-1/2 Ag/Ab 4Th Gen“ with the “HIV DUO assay” (Roche, HIV DUO) The HIV DUO assay also detects both HIV antibodies and antigen but also has a built in confirmatory test to differentiate the antibodies detected. Positive results are repeated and confirmed immediately and will be reported as “repeatedly reactive”. No additional antibody differentiation required (no send out reflex will be performed). A separate blood sample is still required for qualitative or quantitative PCR to establish definitive diagnosis and viral titer.

STAT Policy Change

Providers should only order STAT if they are able to receive the results in the next 2-6 hours and expect patient management to change in the next 12 hours based on the results. Alternatively, all assays on our STAT menu are finalized by next morning at 8am when ordered as routine test.

STAT results will be available through EMR, Fax, printing, etc.; however, a client service representative will no longer call normal or slightly abnormal results as of March 20th. Critical and alert values will be communicated as soon as results are finalized. Please be ready to receive such calls in a timely manner. Please indicate on the requisition form the phone number you would like us to call if no one is at your office. If you wish to continue to receive phone calls on all of your STAT results, please contact your client service representative.

Also, please be aware that when STAT testing is requested, the laboratory needs to divert resources from normal procedures, which may affect turnaround times for routine specimens. We reserve the right to add a stat fee charge to provide this expedited service. Thank you for your consideration and cooperation in using healthcare resources mindfully.

If you have any questions, please reach out to Dr. Zoltan Nagymanyoki M.D, Ph.D., MBA, medical director at znagymanyoki@westpaclab.com.