Vitamin B7
Code:12011|CPT:84591|LOINC:1980-2
| Includes | Vitamin B7 |
|---|
Analysis details
Methodology
- Liquid chromatography–tandem mass spectrometry (LC-MS/MS)
Expected Turnaround Time
1–2 days
Special Instructions
- Avoid smoking for at least 30 minutes before the blood draw.
How to use
The Vitamin B7 (biotin, vitamin H) test is used to assess biotin status and identify deficiency. It is appropriate for individuals with risk factors such as inadequate dietary intake, malabsorption syndromes, pregnancy, anticonvulsant therapy, and prolonged or repeated antibiotic exposure. This measurement can also aid the diagnostic workup of inherited disorders of biotin metabolism, including biotinidase deficiency and multiple carboxylase deficiency.
Limitations
Biotin (vitamin B7; vitamin H; coenzyme R) is a water‑soluble member of the B‑complex. Water‑soluble vitamins are not stored in substantial amounts and excess is eliminated in urine, necessitating an ongoing dietary supply. Limited endogenous production occurs through colonic microbiota. As a cofactor for carboxylase enzymes, biotin supports pathways governing carbohydrate and lipid metabolism, contributes to glycogen synthesis and protein utilization, and is important for integumentary and neurologic function. Dietary sources include whole grains, yeast, egg yolk, dairy products, meat and offal (liver, kidney), legumes, nuts, vegetables, and fruits. Heat processing diminishes B‑vitamin content, and alcohol, nicotine, and caffeine can promote degradation. Clinically significant hypervitaminosis is rare.
| Unit | ng/mL | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Reference interval |
| |||||||||
| Indications | Concern for biotin deficiency due to poor dietary intake, Altered gut microbiota (gastrointestinal dysbiosis), Current anticonvulsant therapy, Extended or repeated courses of antibiotics, Pregnancy, Malabsorption disorders, such as celiac disease, cystic fibrosis, inflammatory bowel disease, or pancreatic insufficiency, Active tobacco use, Paresthesias—numbness, tingling, or burning sensations, Inflammatory skin disease (eczema, dermatitis, psoriasis) or acneiform eruptions, Anemia, Hypercholesterolemia, Hyperglycemia, Developmental delay or hypotonia in children, Hair thinning or loss, alopecia, or premature canities (early graying), Suspected inherited defects of biotin metabolism (biotinidase deficiency, multiple carboxylase deficiency) |
Specimen Requirements
| Specimen | Serum |
|---|---|
| Container | Gold/Tiger Top (SST, Gel Separator) |
| Volume | 1 mL (min 0.5 mL) |
| Storage Instructions | Room temperature, Refrigerated, Frozen |
References
Henry's Clinical Diagnosis and Management by Laboratory Methods, 23rd ed. McPherson RA, Pincus MR. St. Louis, MO: Elsevier; 2016:424–425.
Clinical Laboratory Diagnostics: National Guidelines. Vol 1. Eds. V.V. Dolgov, V.V. Menshikov. Moscow: GEOTAR‑Media; 2012:248–249.