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PTD - 289

Test Directory -  SHBG

Synonyms

Sex Hormone Binding Globulin

Clinical Indications

SHBG is the major serum testosterone binding protein and binds over 70% of testosterone. SHBG levels are suppressed by increased androgen levels and elevated by increased oestrogen (e.g. during pregnancy or treatment with some oral contraceptives). The primary reason for measurement of SHBG is to calculate free androgen status from total tesosterone levels and is useful if total testosterone levels are borderline. SHBG levels are not helpful in discriminating between groups of patients with suspected androgen excess.

SHBG levels are elevated in thyrotoxicosis and decreased in hypothyroidism and SHBG may be used as a marker of thyroid status in patients with thyroid hormone resistance. 

Request Form 

Combined Pathology Blood form (Yellow/Black or Blue for GP's)

Availability

Referred test: Analysed by Clinical Biochemistry, Southend Hospital, if specific criteria met.

Specific Criteria

Female total testosterone greater than 1.5 nmol/L or borderline/low male testosterone. Assessment of thyroid status in thyroid hormone resistance. Otherwise if requested by Consultant Endocrinologist or agreed with Consultant Biochemist.

Patient Preparation

None required.

Turnaround Time

2 weeks

Specimen

Serum

Volume

0.5 mL

Container

Yellow top (SST) tube

Causes for Rejection

Not meeting specific criteria for analysis. Unlabelled sample.

Reference Ranges

Patient group

SHBG (nmol/L)

Male (under 50 years)

18 - 54

Male (50 years and older)

21 - 77

Female (under 50 years)

32 -128

Female (50 years and older)

24 - 128

If total testosterone measured a free androgen index (FAI) will be calculated and reported.

Patient group

Free Androgen Index

Male (under 50 years)

35 - 150

Male (50 years and older)

25 - 150

Female (under 50 years)

Less than 6

Female (50 years and older)

Less than 4

Reference: Southend Clinical Biochemistry

Lab. Handling

Processing: Aliquot (MPA) and store at 4C in separating fridge (CB39). Referral:  SHBG and send or NOSBG and save in separating freezer (CB40) at -20C, saved frozen rack.


Version 1.1 / September 2014                                                                                                 Approved by: Consultant Biochemist