The War on Heterophilic Antibody Interference

Spurious elevation of serum PSA after curative treatment for prostate cancer: clinical consequences and the role of heterophilic antibodies

“…Because of the natural variability in heterophilic antibodies, they can be difficult to identify and remain a challenge for laboratory technicians and physicians alike. 29 Alternatively, there are other sources of error that may contribute to inaccurate PSA readings in the preanalytical, analytical, and/or post-analytical phases of testing. 2 For instance, abnormal test results may occur if serum is not stored or centrifuged properly, if the detection assay is not accurately calibrated, or if serum is obtained after manipulation of the prostate.…”

The measurement of free thyroxine by isotope dilution tandem mass spectrometry

“…It was clear that while immunoassays for T4 gave somewhat higher results than LC/MS/ MS, they correlated fairly well with results by LC/MS/MS with the single major exception of pregnant women (r =0.802-0.900). The poorer correlation in pregnancy can be ascribed to the hormonal changes in the course of pregnancy followed by changes in binding proteins and in part to the presence of heterophilic nonspecific antibodies in this population [11][12][13][14]. The pregnant woman is carrying a "foreign body" and therefore it is not surprising that nonspecific heterophilic antibodies are produced in this population.…”

When laboratory tests can mislead even when they appear plausible

“…A more realistic general 'guestimate' in practice would be 0.4-1%, which is still high; hence the need for awareness and caution. [1][2][3][4][5][6][7][8][9] Probabilistic reasoning based on Bayesian inference, which takes into account key relevant information such as the rate of analytical inherent error and disease prevalence/incidence, is a concept that can help in identifying potentially false results and quantifying the likelihood of false positive and negative data.…”

“…10,11 The immunoassay used to measure TSH may be assumed to have an excellent diagnostic accuracy of 99.6% and an error rate of ±0.4% (considered among the lowest reported). [1][2][3][4][5][6][7][8][9] This means four false positives or negatives are predicted per thousand in any population sample.…”

“…Unquestioning acceptance at face value may lead to misdiagnosis and mistreatment or unnecessary surgery for unconfirmed disease with consequent iatrogenic morbidity. [1][2][3][4][5][6][7][8][9] A probabilistic rationale based on Bayes' theorem 1 -in which key information, such as (a) the rate of inherent analytical error in a test and (b) the disease prevalence (number of cases per head of ABSTRACT When laboratory tests can mislead even when they appear plausible population) or incidence (rate of new cases over a period of time), is taken into account -can be used to evaluate the likelihood of an erroneous result occurring and its nature, ie false positive or false negative. Essentially, in disorders with low prevalence/incidence and/or when a test is used as a screen with vague or insufficient clinical correlates, erroneous results are likely to be false positives.…”