Tube type:

   One 6.0 mL PST (Green) tube or

   One 6.0 mL SST (Gold) tube.

   One 6.0 mL RED tube (preferred for all Regional Pathology Services clients).
 

Volume Requirement:

   Optimum: 1.0 mL

   Minimum: 0.6 mL

Serum: The gold stopper tube should be allowed to clot before centifuging. Specimens should be centrifuged at minimum 2500 RPM for minimum 5 minutes. Serum should be separated from the cells promptly to an appropriately labeled tube, unless using SST tube.

Plasma: Mix anticoagulant with specimen adequately. Specimens should be centrifuged at minimum 2500 RPM for minimum 5 minutes. Remove plasma promptly from cells to an appropriately labeled tube, unless using PST tube.

Centrifuge and remove serum or plasma from the cells with 2 hours of collection.

Storage:
Plasma:  Room temperature for 8 hours
                Refrigerator temperature for 2 days*
                Freezer temperature up to 2 months 

  Serum: Room temperature for 8 hours
               Refrigerator temperature for 2 days*
               Freezer temperature for up to 2 months

*TST portion of panel only stable for 2 days, SHBG portion of panel stable for 7 days

TSFTST panel includes: SHBG (Sex Hormone Binding Globulin)
                                        TST (Testosterone)
                                        fTST (Free Testosterone)
                                        %fTST (Percent Free Testosterone).

Free Testosterone and % Free Testosterone are ONLY available on TSFTST panel.

Free Testosterone will be based on calculation (not direct measurement) using measured SHBG and total TST in the Vermeulen equation.
% Free Testosterone will be based on calculation using measured SHBG and total TST in the Nanjee & Wheeler equation.

TSFTST panel is NOT available for females and males <14 years of age.

 As testosterone is bound and carried not only by SHBG, but also by albumin, significant changes in serum albumin concentration will trigger changes in the value of calculated free testosterone. In theses circumstances (e.g. patients with renal diseases, liver diseases, chronic inflammation, malnutrituion, etc.), the calculated fTST can be corrected to account for albumin concentration. This correction will be available only upon request and only in justified medical circumstances (e.g. medical conditions associated with significant decreased serum albumin concentration). This correction will involve measurement of albumin in the patient's serum (same sample as the one used for evaluation of fTST). Due to sample stability, this correction can be followed only within five days from the evaluation of fTST.

Testosterone Ranges:

Male:  14-18 years 100-950 ng/dL
Male:  >18 years  250-950 ng/dL

Free Testosterone Ranges (Vermeulen equation)
Adult males > 14 yrs.:                             38.0-311.0 pg/ml

Percentage Free Testosterone (Nanjee & Wheeler equation):
Adult males > 14 yrs.:                             1.6-2.9%

SHBG Ranges:
Adult males > 18 yrs:                             17-125 nmol/L