Clinical judgement perplexed by initially undisclosed use of herbal medicine and unexpected cross-reactivity of immunoassay
- Author:
Kuan-Ting Liu
;
Chi-Wei Lee
- Publication Type:Case Report
- Keywords:
ginsenoside;
digoxin-like substances;
immunoassay;
cross-reactivity
- From:The Malaysian Journal of Pathology
2017;39(2):189-192
- CountryMalaysia
- Language:English
-
Abstract:
We report a case of symptomatic bradycardia caused by consumption of a Chinese herbal medicine
which was initially undisclosed to the attending emergency physician. The scientific name of the herb
is Panax japonicus. Electrocardiogram revealed sinus bradycardia. Laboratory tests were normal
except for the detection of a high serum digoxin level. Further interrogation of the patient eventually
disclosed ingestion of the herb which, however, did not contain any digoxin. Other active ingredients
in the herb include various types of ginsenoside. These are digoxin-like substances that had caused
the observed false-positive detection of digoxin by fluorescence polarization immunoassay due to
cross-reactivity. Our case-report provides an important insight about a blind-spot in the field of
laboratory medicine (clinical pathology), namely, the false positive detection of digoxin due to crossreactivity
in the immunoassay when we come across digoxin-like substances in clinical scenarios,
which has barely received attention in the medical literature. It also conveys a clear educational
message that with full understanding of the laboratory methodology and its mechanistic rationale
there are actually some tricks-of-the-trade that allow us to optimize the specificity of the biochemical
tests and the treatment of digoxin-like substances overdose.
