Specimen Requirements

Preferred Collection Container: 

Light Green (Lithium Heparin Plasma Separator Tube)
SST (Serum Separator)

Also Acceptable Collection Container: 

Green No Gel (Lithium Heparin)
Red (No Additive)

Collection Information: 

Collect blood in a Light Green (Lithium Heparin Plasma Separator Tube) or SST (Serum Separator). Green No Gel (Lithium Heparin), Red (No Additive) also acceptable.

Transport Information: 

Centrifuge and aliquot 1.0 mL of serum or plasma into a plastic transport vial. Send refrigerated.

Minimum Sample Volume: 

0.5 mL of serum or plasma

Remarks: 

Serum concentrations of testosterone in both sexes during the first week of life average about 25 ng/dL. In male infants, values increase sharply in the second week to maximum (mean about 175 ng/dL) at about 2 months, which lasts until about 6 months of age. In female infants, values decrease in the first week and remain low throughout early childhood. Levels increase during puberty to adult values and are related to the pubertal stage rather than chronological age.