Interference by Human Anti-mouse Antibodies in Immunoassays: Falsely Elevated Cardiac Troponins Leading to Negative Coronary Angiograms
Mian Bilal Alam *
Department of Internal Medicine, University of Pittsburgh Medical Center (UPMC), Pittsburgh, PA, United States of America.
Surachit Kumar
Department of Internal Medicine, Conemaugh Memorial Medical Center, Johnstown, PA, United States of America.
Ibrahim Sbietan
Department of Internal Medicine, Conemaugh Memorial Medical Center, Johnstown, PA, United States of America.
K. M. Anwar Hussain
Department of Internal Medicine, Conemaugh Memorial Medical Center, Johnstown, PA, United States of America.
Mehwish Asad
Department of Internal Medicine, Conemaugh Memorial Medical Center, Johnstown, PA, United States of America.
Asif N. Khan
Department of Internal Medicine, Charleston Area Medical Center, Charleston, WV, United States of America.
*Author to whom correspondence should be addressed.
Abstract
Cardiac Troponins are an extremely important indicator of myocardial injury and American College of Cardiology (ACC) and American Heart Association (AHA) guidelines include Cardiac Troponins as one of the major diagnostic criteria for myocardial damage. However in some instances the presence of heterophilic antibodies like Human Anti-Mouse Antibodies (HAMA) may interfere with the sandwich assays used for the detection and quantification of cardiac troponins giving false results which can have a major impact on the management of an individual suspected to have myocardial injury.
We present a case of a 56 year old Caucasian male who had negative coronary angiogram 2 years ago presenting with acute chest pain and significantly elevated levels of Cardiac Troponin I (cTnI). He underwent cardiac catheterization which again turned out to be completely normal. His cTnI levels continued to be consistently elevated for months after cardiac catheterization. The reason for elevated cTnI levels was due to high levels of HAMA antibodies that caused heterophilic antibody interference in the assay of cTnI, resulting in falsely elevated levels of cTnI.
Keywords: Cardiac troponin I (cTnI), cardiac troponin T (cTnT), human anti-mouse antibodies (HAMA), heterophilic antibodies