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Laboratory:

Clinical Biochemistry (AUTOMATED)

Test Name:

TESTOSTERONE TOTAL, BIOAVAILABLE and FREE (CALCULATED) - (P)

Test Code: FTST

Clinical Information:

Description: Provides a calculated value for bioavailable and free testosterone concentration using measured total testosterone (immunoassay), sex hormone binding globulin (SHBG) and albumin levels.

Test Indications: It is useful in evaluation of hypogonadism in males with low total testosterone levels or in individuals with altered protein binding. It may also be used to monitor testosterone hormone therapy. It is not recommended for children or females.

Patient preparation instructions: Fasting is preferred, but not required.

Collection Devices:

Preferred Device:

1 - Li Heparin Plasma Separator Tube(s) - Full Tube Collection

Li Heparin Plasma Separator Tube(s) - Full Tube Collection
Manufacturer: BD (Becton Dickinson)

Catalogue #: 367962

Acceptable specimen include serum with or without gel

Specimen Required:

Plasma: 2.0 mL

Collection Information: Collect morning specimen (6 AM-10 AM).
Special Processing: Samples must be transferred to an aliquot tube and stored frozen if analysis will not be complete within 48 hours.
Specimen Stability:
Ambient: 48 h
Refrigerated: 1 week
Frozen: 2 months

Referral:

Plasma: 2.0 mL

Requisition:

_SH General Endocrinology Requisition (R250-10-76)

_SH Specialized Endocrinology Requisition (R250-10-77)

Reference Values:

Test	Male 20-49 years	Male ≥50 years	Female 20-49 years	Female ≥50 years
Bioavailable testosterone, nmol/L	4.36-14.3	3.59-11.0	0.06-0.80	0.03-0.43
Free testosterone, nmol/L	0.20 - 0.62	0.16-0.47	<0.03	<0.02
Free testosterone percentage, %	1.5-2.9	1.2-2.6	0.7-2.2	0.7-2.6

Reference intervals are based on 5th – 95th percentiles and morning blood collection.

Method of Analysis: Roche electrochemiluminescence immunoassay / Calculation

Availability:

Routine