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Test Code Biotinida Biotinidase, Quantitative

Clinical System Name

Biotinidase, Quantitative


This test is used to diagnose biotinidase deficiency in clinically symptomatic patients and to confirm the diagnosis suspected from abnormal newborn screening.

Sample Requirements

Specimen: Whole Blood

Container(s): Dark Green/Sodium Heparin, Lt. Green/Lithium Heparin Microtainer

Preferred Vol:1.0 mL

Minimum Vol: 0.5 mL


Note: Red and gold top tubes are acceptable but not preferred.

Processing Instructions

Reject due to:

Spin: Y

Aliquot: Y

Temp: -20 C

Storage location: Aliquot 0.2 mL plasma and store in CPA Freezer, Biochemical Genetics box


Off-site collection: Spin blood, freeze plasma within 2 hours. Ship sample frozen.


Temperature Time
Room temp ≤2 hrs
Refrigerated ≤2 hrs
Frozen 7 days (-20 C), 1 month (-70 C)



STAT Performed TAT
N Weekly 1 week


Contact the Biochemical Genetics Lab for requests outside of stated availability (206)987-2216.


Department: Biochemical Genetics

Phone: 206-987-2216



Reference Range

Normal (nmol/min/mL) 5.5 - 17
Partial deficiency 2.0 - 5.4
Deficient 0 - 1.9



Method: Enzymatic/Spectrophotometric

Analytical Volume: 0.2 mL plasma

Limitations: Biotinidase cannot be performed if patient is on a sulfonamide antibiotic.

CPT Codes



Biochemical Genetics Requisition


On the requisition include clinical information needed for appropriate interpretation. (Age, gender, drug therapy and family history)

Clinical Utility

Profound biotinidase deficiency can be characterized by seizures, hypotonia, ataxia, developmental delay, vision problems, hearing loss, and cutaneous abnormalities such as alopecia, skin rash, and candidiasis. Individuals with partial biotinidase deficiency may have hypotonia, skin rash, and hair loss, particularly during times of stress. Once vision problems, hearing loss, and developmental delay occur, they are usually irreversible even with biotin therapy.


Individuals with profound biotinidase deficiency have lower than 10% of mean normal serum biotinidase activity. Individuals with partial biotinidase deficiency have 10-30% of mean normal serum biotinidase activity. Both profound and partial biotinidase deficiency are usually identified by newborn screening.


Children with biotinidase deficiency remain asymptomatic if biotin therapy is instituted early and maintained continuously.