TESTOSTERONE - (P)

Test Code: TST

Test Indications: Testosterone levels are used for the assessment of individuals with clinical symptoms suggestive of androgen deficiency or excess. This includes:
Evaluation of infants with ambiguous genitalia or virilization
Evaluation of boys with delayed or precocius puberty
Monitoring of testosterone replacement or antiandrogen therapy
Women with infertility, hirsutism, virilization or oligomenorrhea
Diagnosis of androgen-secreting tumors
Endocrine Society Clinical Practice Guidelines recommend against screening for androgen deficiency in the general population. J. Clin Endocrinol Metab June 2010, 95 (6): 2536 - 2559
In rare cases, substances that alter the measurable concentration of the analyte in the sample or alter antibody binding in the assay may be present in serum. These can result in assay interference due to interraction with one or more reagent antibodies or components and cause falsely elevated or falsely decreased test results. These include structurally similar compounds that cross react with the antibody, heterophile antibodies, human anti-animal antibodies, autoanalyte antibodies, rheumatoid factors and other proteins. Clin Biochem Rev May 2004, 25: 105 - 120
Contact the on-call clinical biochemist if test results are inconsistent wth the clinical picture.

Recommendations: Endocrine Society Clinical Practice Guidelines recommend making a diagnosis of androgen deficiency only in men with consistent symptoms and unequivocally low serum testosterone levels. Morning (0700 - 1000h) fasting samples, collected on two or more occassions to minimize biological variability, are recommended for the assessment of male hypogonadism. The evaluation of androgen deficiency should not be made during an acute or subacute illness. J. Clin Endocrinol Metab June 2010, 95 (6): 2536 - 2559

Patient Preparation Instructions:  This test is unaffected by multivitamins (45 - 125 µg biotin) or biotin-only supplements.

Morning (0700 – 1000h) fasting samples, collected on two or more occasions to minimize biological variability, are recommended for the assessment of male hypogonadism.

_SH Endocrinology (General) Primary Care Requisition (R250-10-76)

_SH Endocrinology (Specialist) Requisition (R250-10-77)

Female:
    0 - 4 wk:       0.7-2.2 nmol/L
    5 wk - 12 y:    <1 
    ≥ 13 y:          0.5-2.4 

Male:
    0 - 7 mo:      2.6-14    
    8 mo - 12 y:   <1
    ≥ 13 y:           9.7-38                   (nmol/L x 28.8 = ng/dL)

Daily

Albumin will automatically be added to all Testosterone requests in male older than 17 years. if Testosterone is an add-on, please ensure albumin is manually added as well.If Bioavailable Testosterone requested, it may be substituted with FAI (TST and SHBG)