A clinical and laboratory approach used to elucidate discordant results of high-sensitivity troponin T and troponin I

• Published in: Clinica chimica acta 2015-06, Vol.446, p.128-131
• Main Authors: Franeková, Janka, Bláha, Martin, Bělohoubek, Jiří, Kotrbatá, Markéta, Sečník, Peter, Kubíček, Zdenek, Kettner, Jiří, Jabor, Antonín
• Format: Article
• Language: English
• Subjects: Aged; Animals; Antibodies, Monoclonal - chemistry; Back Pain - blood; Back Pain - complications; Back Pain - pathology; Bundle-Branch Block - blood; Bundle-Branch Block - complications; Bundle-Branch Block - pathology; Chest Pain - blood; Chest Pain - complications; Chest Pain - pathology; Diabetes Mellitus, Type 2 - blood; Diabetes Mellitus, Type 2 - complications; Diabetes Mellitus, Type 2 - pathology; Dyslipidemias - blood; Dyslipidemias - complications; Dyslipidemias - pathology; False Positive Reactions; Female; Heterophile antibodies; Humans; Hypertension - blood; Hypertension - complications; Hypertension - pathology; Immunoassay; Immunoassay interference; Immunoglobulin M - blood; Mice; Osteoporosis - blood; Osteoporosis - complications; Osteoporosis - pathology; Reference Values; Troponin; Troponin I - blood; Troponin T - blood
• ISSN: 0009-8981; 1873-3492
• DOI: 10.1016/j.cca.2015.03.046

Careful interpretation of discordant results in high-sensitivity troponin measurements is necessary in cases of suspect immunoassay interferences. We describe several procedures taken in a case of a polymorbid patient with chest pain, without clear evidence of myocardial necrosis and with increased high-sensitivity cardiac troponin T (hs-cTnT). We checked the Vafaie's algorithm for the evaluation of suspect interference in troponin measurements. We conducted a case report analysis, additional measurements, a dilution test and pretreatment of plasma with blocking agents. Concentration of hs-cTnT (99th percentile of “healthy” population 14ng/L) increased from 120.1ng/L to 280.4ng/L during an 8-month period and decreased to 216.3ng/L during the following month with repeatedly negative troponin I (TnI), hs-cTnI, myoglobin and creatine kinase MB (CK-MB). Suspected false positivity of hs-cTnT was further confirmed by treatment of plasma with an antiheterophile blocking agent (hs-cTnT before treatment 280.4ng/L, after 16.53/16.23ng/L). This outcome was further confirmed by the manufacturer's experiments. The false-positive results of hs-cTnT were caused by the presence of extremely rare high molecular weight protein, presumably IgM, most likely HAMA (human anti-mouse antibody). Only the pre-treatment of plasma with a blocking agent provided a reliable indication of the interference. Cooperation among clinicians, laboratory personnel and the manufacturer is essential. •Rare false-positive interference in the troponin measurement is described.•Multiple procedures should be taken when immunoassay interferences are suspected.•Using of heterophilic blocking tubes was the most effective procedure.