The real-world rate of falsely reduced cardiac troponin T tests

Objectives Measurement of cardiac troponin T (cTnT) plays a crucial role in the diagnosis of acute myocardial infarction (AMI). Due to its extremely high sensitivity, the high sensitive troponin T test is vulnerable to interfering antibodies. Development of antibodies against troponin T is an example of “autoimmunization” due to an altered self. Incorrect, reduced troponin T test results are commonly observed with a deviation of more than 40 % compared to the real value. According to literature 10–20 % of measurements reveal such inaccurate results. This rate is even higher in the most relevant risk group, patients who already had suffered from an AMI. Methods For this purpose, we spiked serum samples with a defined amount of recombinant troponin T and analyzed the recovery rate. Here, a differing result indicates presence of troponin T analyte interference. 147 consecutive selected samples with cTnT results up to 200 pg/mL were reanalyzed for a negative interference of the test by adding recombinant troponin T protein as a spike to each serum sample and thereafter retesting the sample again. Results 35 % of the samples (n=51) had an interference of at least 40 %, an interference of at least 80 % was found in 10 % (n=12). Conclusions This means, that in 10 % of the patients a clinically relevant masked laboratory test result was observed, revealing at least fivefold higher troponin concentrations than reported by routine analysis.