Supplementary medication in multiple sclerosis: Real-world experience and potential interference with neurofilament light chain measurement

Background

As vitamins and dietary supplements are obtainable without prescription, treating physicians often ignore their intake by patients with multiple sclerosis (MS) and may therefore miss potential adverse effects and interactions.

Objective

We aimed to assess the spectrum and intake frequency of supplementary medication in a cohort of MS patients and to analyse the effect of biotin intake on measurement of serum neurofilament light chain (sNfL), an emerging marker of disease activity.

Methods

MS patients visiting our neurology outpatient clinic completed a questionnaire on their past or present use of vitamins or dietary supplements. In addition, the impact of two different doses of biotin (10 and 300 mg/day) on sNfL was studied in healthy volunteers.

Results

Of 186 patients, 72.6% reported taking over-the-counter vitamins or dietary supplements currently or previously. Most frequently used was vitamin D (60.0%), followed by biotin. Female patients and patients with primary progressive MS tended to use supplements more frequently. Biotin intake did not interfere with sNfL measurement by single molecule array (Simoa).

Conclusions

The use of vitamins and dietary supplements is frequent among patients with MS. Thus, treating physicians should be aware of the pitfalls of supplementary treatment and educate their patients accordingly.

Biotin interferences: Have we neglected the impact on serological markers?

BACKGROUND

Biotin has been reported to be a leading cause of interference on several immunoassay platforms using the streptavidin-biotin immobilization system. While biotin interferences have now been well characterized for several assays, only few data are available on their impact on serological markers of infectious viral diseases.

METHODS

Overall, 10 healthy volunteers (HVs) received a single 100 mg dose of biotin to evaluate its effect on hepatitis B serological markers. Blood samples were taken several times before and after biotin intake. In addition, spiking experiments were applied to investigate biotin's impact on anti-HIV/p24 Ag and anti-HCV antibody levels. Several procedures designed to overcome this interference were evaluated.

RESULTS

Biotin intake resulted in a false-negative anti-HBs immunological status (<10 mIU/mL) in 40.0% of cases. According to our anti-HBc and anti-HBe results, biotin intake was associated with 90.0% and 80.0% of false positive results, respectively. At the theoretical biotin peak concentration following a 100 mg intake, 50.0% and 66.6% of anti-HIV and anti-HCV results were false negatives, respectively. All the procedures evaluated to overcome the interference were proven effective.

CONCLUSION

HBV, HCV, and HIV serological markers are likely to be highly sensitive to biotin. Our data confirm that the scope of biotin interference is broader than commonly described.