Testosterone, Free (Direct)

Fasting Required
CPT: 84402
Hormones

What This Test Measures

Directly measured free testosterone via equilibrium dialysis; most accurate method for free T.

Preparation

Fasting required (8-12 hours)
Draw in the early morning (7–10 AM) when testosterone is at its daily peak. If on testosterone BHRT injections, draw at trough — just before your next scheduled injection — for the most clinically meaningful result. Quest may report inflated values for women on BHRT; CPL or LabCorp recommended for trending.
💬 Patient Community Notes

TRT TIMING: Draw at trough — just before your next injection. NOTE: The direct free testosterone assay (analog/RIA) is widely considered less accurate than the calculated method, especially at low levels. Many functional practitioners and the TRT community prefer calculated free T or equilibrium dialysis. For women on BHRT, use LC/MS/MS methodology. These notes reflect common practices in TRT/BHRT communities.

Reflects common practices in thyroid, BHRT, and functional medicine communities. This may differ from standard clinical guidelines. Not medical advice — always discuss with your provider.

General guidelines only. Requirements vary by lab and individual. Confirm with your provider before adjusting any medications.

Turnaround Time

Varies by lab

Clinical Notes

Gold standard for free T; some DTC platforms offer this specifically

ICD-10 Codes

Common diagnosis codes associated with this test. Codes are assigned by your provider.

E28.39Other ovarian dysfunction
E29.1Testicular hypofunction
N91.2Amenorrhea, unspecified
R68.89Other specified general symptoms and signs

Self-Pay Pricing

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Ulta Lab Tests

Uses Quest Diagnostics network; generally lowest DTC prices; not available in NY, NJ, RI

$59.00Order
Walk-In Lab

Uses both Quest and Labcorp networks; competitive pricing; broad test selection

$59.00Order
Life Extension

Uses Labcorp network; known for supplement company; competitive lab test pricing

$59.00Order
HealthLabs.com

Uses Quest and Labcorp; strong panel bundling; results in 1-3 days

$69.00Order
Request A Test

Uses Quest and Labcorp networks; offers both individual tests and discounted panels

$79.00Order

Lab Codes

Proprietary codes used by each lab for this test.

ARUP Laboratories
0070111(order)
CPL
4834(order_code)
LabCorp
144980(order)
Mayo Clinic Labs
TGRP(order)
Quest Diagnostics
18944(order)

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For informational purposes only

This page is for educational and research purposes only and does not constitute medical advice, diagnosis, or treatment recommendations. ICD-10 and CPT codes are assigned by your healthcare provider. Always consult a qualified healthcare provider before ordering any lab test or making decisions about your health.