Clinical Toolkit
Four calculators that answer the questions this course keeps returning to. Everything runs in your browser; nothing is stored or transmitted.
Calculated free testosterone
Below the commonly cited lower limit of roughly 64 pg/mL (6.4 ng/dL). Bioavailable testosterone is approximately 124 ng/dL and the free fraction is 1.60%. In a symptomatic man with confirmed low morning totals, this supports the diagnosis. Confirm the reference range for your laboratory.
Use when the total is borderline (roughly 200–400 ng/dL), when symptoms and total disagree, or when an SHBG-altering condition is present. Reference ranges are assay-specific.
Hematocrit action threshold
Hematocrit of 51% is in the 50–53% watch range. Recheck the value. No contributors flagged — still confirm hydration status and the timing of the draw relative to the last dose. Because this is an injectable regimen, the most effective first move is usually to shorten the dosing interval — for example, splitting an every-2-week dose into weekly administration — which lowers the peak without reducing total weekly exposure.
PSA velocity and referral
An absolute rise of 1.50 ng/mL within 10 months exceeds the 1.4 ng/mL in 12 months referral threshold. Confirm the value after excluding confounders — recent ejaculation, prostatitis, urinary instrumentation, cycling — then refer to urology. A normal digital rectal examination does not exclude clinically significant disease.
Also refer for a new palpable nodule or induration, a PSA above the age-appropriate threshold, or significant lower urinary tract obstructive symptoms.
Formulation selector
With no constraints flagged, weekly subcutaneous testosterone cypionate offers smooth kinetics, low cost, no transference risk, and easy titration. Note that subcutaneous administration is off-label for most cypionate products; document the discussion. Draw a trough level and hematocrit at 3 months.
These tools are educational aids and do not replace clinical judgment, current product labeling, or laboratory-specific reference ranges. Calculated free testosterone uses the Vermeulen equation, which approximates equilibrium dialysis but is not identical to it.