Sense and nonsense concerning biotin interference in laboratory tests

[madman]

Sense and nonsense concerning biotin interference in laboratory tests (2020)
Alena Moerman & Joris R. Delanghe


ABSTRACT

Introduction: Biotin supplementation (mainly OTC preparations) has gained popularity. There are concerns about biotin interference in immunoassays and potential misdiagnosis, especially since the discovery of high-dose therapy in MS. This review summarizes the dangers of biotin usage and possible countermeasures.

Methods: Immunoassays design determines whether positive or negative analytical errors may occur. Techniques using biotinylated reagents and biotin-binding proteins may generate errors. In sandwich immunoassays, biotin causes lowered results. Competitive immunoassays are more vulnerable: biotin usage causes false increased results. The interference is platform-dependent. Parameters vary in their susceptibility: a combination of false positives and negatives mimicking a coherent profile is dangerous, e.g. combining falsely lowered TSH with falsely elevated FT4/FT3 mimicking hyperthyreosis. Other susceptible parameters are thyroglobulin, DHEA-S, estradiol, testosterone, ferritin, progesterone, Vitamin D, Vitamin B12, PSA, PTH, LH, FSH, Troponins I and T, Pro-BNP. Digoxin and PSA may also be affected. Tumor markers and ßhCG are robust. Inserts of serological markers of HIV, hepatitis B, and C warn of biotin interference.

Results: Manufacturers have made assays less vulnerable to biotin interference. In doubtful cases, it is helpful to determine testosterone in females and estrogen in males. Both are elevated if biotin interference is present. Biotin supplementation should be discontinued. However, this is impossible in MS patients needing biotin, as interrupting this medication is discouraged.

Conclusions: Solutions to overcome this interference are: informing patients prior to analysis (avoiding peak biotin values when sampling), choice of appropriate immunoassays, and use of biotin removing steps prior to analysis.




Conclusion

The problem concerning biotin and its interference in immunoassays is real and should not be minimized. It is expected that the magnitude of the issue will only increase since the OTC and mainly pharmacologic usage will continue to rise. Alertness and awareness are the keys to the solution. When the problem is noticed in time, there are a number of strategies to overcome this interference: informing the patient prior to analysis (avoiding peak biotin values at the moment of sampling), choice of appropriate immunoassays, and (in case of doubtful result), use of biotin removing steps prior to analysis).

 

[madman]

Figure 1. Display of the mechanism of biotin interference in immunoassays.

 

[madman]

Table 1. Summary of the different parameters with corresponding platforms, their susceptibility to biotin and an indication of whether they show positive or negative bias [28].

Parameters in bold are easily influenced (concentrations < 40 ng/mL), others are somewhat more resistant (concentrations from > 40 to 100 ng/mL) and the parameters in italic are those that will only be affected at concentrations of more than 100 ng/mL of biotin. The exact concentrations at which interference occurs is platform dependent. This table was made using the Roche platform as standard to which others were compared. Some known very susceptible parameters (for example FT3 and FT4) are not represented in bold because the reagent has been adapted and newer generation reagents are already widely used.

 

[fifty]

I would file this under #notmyproblem. Fix the assays.

 

[Nixter]

Those explains my recent e2 reading of 190

 

[Nelson Vergel]

If you use LC/MS for estradiol and testosterone, this is not a problem.

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[madman]

Suspected Testosterone-Producing Tumor in a Patient Taking Biotin Supplements

We report a case of biotin interference with endocrine laboratory testing, which nearly resulted in an unnecessary surgical procedure.

academic.oup.com

*Ten weeks after initial presentation, the patient’s free and total testosterone were measured using liquid chromatography-tandem mass spectroscopy (LC-MS/MS) and found to be within reference intervals (Table 1). Health care professionals in the laboratory were consulted regarding the differing measured testosterone concentrations. A pattern was identified consisting of aberrant hormones by competitive and immunometric immunoassays compared with normal hormone measurements by LC-MS/MS (Table 1). Notably, tests via LC-MS/MS are not prone to biotin interference. Collectively, these findings suggested potential biotin interference with immunoassay testing as a cause for the patient’s aberrant hormonal profile. Ten weeks after presentation, our patient’s sample was thus tested for biotin by LC-MS/MS (research use only), which measured a biotin concentration of 38 ng/mL (Table 1).

 

[GreenMachineX]

How much biotin would cause this issue? There's biotin in my wife's multi and we've suspected her to be hypothyroid, but her levels are always normal yet close to the low side.