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Diagnostic Services

Genetics Lab


Biotinidase Enzyme Assay

Biotinidase deficiency is an autosomal recessive disorder of biotin recycling with an estimated incidence of 1:60,000. Deficiency of the biotinidase enzyme will result in decreased levels of free biotin, impairing the activity of multiple biotin-dependent enzymes. If untreated, patients with profound biotinidase deficiency may exhibit seizures, hypotonia, ataxia, developmental delay, vision problems, hearing loss, and cutaneous abnormalities such as alopecia, skin rash, and candidiasis. With age, motor limb weakness, spastic paresis, and decreased visual acuity occur. Once vision problems, hearing loss, and developmental delay occur, they are usually irreversible even with biotin therapy. Untreated patients with partial biotinidase deficiency may have hypotonia, skin rash, and hair loss, particularly during times of stress.

Test Name: Biotinidase serum
Test Code:
Test Description:
Quantitative measurement of biotinidase activity in serum.
This test is used to diagnose biotinidase deficiency in clinically symptomatic patients and to confirm the diagnosis suspected from abnormal newborn screening.
Related Tests:
Clinical Links: Biotinidase Deficiency GeneReview
Turnaround Time:
1 week
Reference Range:
5.5 - 14 nmoles/min/mL
Consent Form:
Sample Requirements: Type
Whole blood: 1 mL Green (Heparin), Red or Gold Top Tube

Spin blood, freeze serum.

Ship sample frozen.
Samples Received:
Mon – Fri 8:00 am – 5:00 pm PST
Special Considerations:
Please e-mail Client Services or call at 206-987-2617 with any billing questions
CPT Code:
Please e-mail Client Services or call at 206-987-2617 with any billing questions