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← All articlesA testosterone test in Tarzana is a morning blood draw, ideally before 10 AM and fasting, that measures total testosterone and, when the first number is borderline, free testosterone and the protein that carries it. One result is never a diagnosis. The guidelines that our provider follows require two low readings on separate mornings plus real symptoms before anyone is called testosterone deficient. This guide covers when to have blood drawn, what to ask for on the order, what the numbers mean, the mistakes that produce false lows and false normals, and what happens after the result comes back.
Testosterone follows a daily rhythm. In most men it peaks in the early morning and falls through the afternoon, and in younger men the afternoon value can sit well below the morning one. A draw at 4 PM can turn a normal man into a "low" one on paper. That is why both the American Urological Association and the Endocrine Society ask for early-morning samples, and why a result from a random afternoon visit should be repeated before anyone acts on it.
Food matters too. A 2016 study presented to the Endocrine Society gave 74 men a standard glucose load and watched testosterone drop in the hours afterward. The Endocrine Society guideline now specifies a fasting morning sample as the first test. Water is fine. Breakfast, coffee with sugar and a protein shake are not.
Two other things move the number for days at a time: acute illness and short sleep. A bad cold, a hard week of four-hour nights, or a recent surgery can push testosterone down temporarily. If any of those apply, wait two weeks and then test. Our lab testing page explains how the draw is ordered and where it is done.
This is the first and most important number, and the one everything else hangs on. Ask that it be run on an assay certified by the CDC Hormone Standardization Program. That matters more than most people realize. A CDC-linked review of proficiency testing found results for the same sample varying by as much as 130 percent between laboratories and methods, and a laboratory-benefits bulletin estimated that only about 40 to 50 percent of labs use standardized testosterone tests. The big national labs, including the Quest draw sites in Tarzana, run certified methods. A result from an unstandardized assay is a guess with a decimal point.
Most testosterone in the blood is bound to sex hormone-binding globulin, SHBG, and is not available to tissues. SHBG rises with age and falls with obesity, and those two effects pull total testosterone in opposite directions. A heavier man can show a low total with a normal free level, and an older lean man can show a normal total while the free fraction is low. The Endocrine Society recommends free testosterone, measured by equilibrium dialysis or calculated from total testosterone, SHBG and albumin, whenever the total is near the lower limit or a condition that alters SHBG is present. Ask for it up front if you carry extra weight or are over 50. It saves a third draw.
Luteinizing hormone, LH, is the pituitary's signal to the testes. If testosterone is low and LH is high, the testes are not responding, which is called primary hypogonadism. If testosterone is low and LH is low or low-normal, the signal itself is weak, and the AUA guideline then calls for a prolactin level, because a pituitary problem can be the cause and needs its own evaluation. This distinction changes the treatment conversation, so it belongs on the first panel, not the third.
If the result could lead to therapy, the AUA asks for two more numbers before anyone starts: hemoglobin and hematocrit, because testosterone raises red cell count and the guideline wants hematocrit under 50 percent at baseline and under 54 percent on treatment, and PSA for men over 40. Estradiol is optional at baseline and recommended when there are breast symptoms. We draw these with the first panel so a man who qualifies does not wait another two weeks for the second draw.
The symptoms that bring most men in, fatigue, low drive, brain fog, stubborn belly fat, overlap with thyroid disease, prediabetes and sleep disorders. Thyroid-stimulating hormone, an A1c and a lipid panel on the same draw cost little and answer the question "if it is not testosterone, what is it?" Our post on feeling tired all the time walks through that overlap.
The AUA uses a total testosterone below 300 ng/dL as a reasonable cutoff in support of the diagnosis, and it is explicit that the number alone is not enough: the diagnosis is made only when two early-morning values are low and the man has symptoms or signs. A single low result, or a low result in a man who feels fine, is not a diagnosis of anything.
The reference range printed on your report is another thing to read carefully. In a landmark harmonization study, samples from four large cohorts were measured at the CDC, and the harmonized normal range for non-obese men aged 19 to 39 came out at 264 to 916 ng/dL. That range comes from young, non-obese men. Older men run lower on average, and "normal for your age" is a statistical statement, not a verdict on how you feel. A 55-year-old at 320 ng/dL with every symptom on the list and a 55-year-old at 320 ng/dL who feels great are not the same patient, which is why the provider, not the printout, makes the call.
Free testosterone is where the ranges get messy. Different calculators give different answers, and a 2024 review flagged the lack of standardization. The practical rule: if your total is clearly low on two draws, free testosterone adds little. If your total is borderline, the free fraction decides, and it should be measured the same way each time so the numbers can be compared.
At Contour Medical Clinic the draw is ordered after a free consult, done at a Quest site near you, and reviewed by our provider with you on a call. Three outcomes are possible.
Both morning values low, symptoms present. The provider explains the options, what monitoring looks like, and what the FDA's 2025 labeling change means for the risks you should weigh. Our posts on how long testosterone therapy takes to work and what happens if you stop cover the two questions men ask next, and the cost guide explains what a program includes.
Borderline. Free testosterone and SHBG decide, and sometimes a third morning draw. This is the group where a careful clinic earns its keep and a careless one writes a prescription.
Normal. Good news with a catch: the symptoms are real and are coming from somewhere else. Thyroid, sleep apnea, prediabetes and depression are the usual suspects, and the same draw usually points to one of them. You leave with an answer, not a prescription.
Whatever the result, the provider decides whether treatment is appropriate, and the decision waits for both draws. Men come to us from Tarzana, Encino, Woodland Hills and Sherman Oaks, and the guide to choosing a TRT clinic lists the questions worth asking any of them, including ours.
Between about 7 and 10 AM, fasting, on a normal day when you are not sick and have slept. Both major guidelines specify early morning, and the Endocrine Society specifies fasting.
Yes, if the first is low or borderline. The AUA and the Endocrine Society both require a second early-morning value on a separate day before a diagnosis. A single result is a reason to repeat, not a reason to treat.
The harmonized range for non-obese men aged 19 to 39 is about 264 to 916 ng/dL, and the AUA treats below 300 as a reasonable cutoff when symptoms are present. Ranges differ by lab and by age, and the number only means something next to how you feel.
Tell the provider what you take. Opioids, some steroids, certain antidepressants and over-the-counter "testosterone boosters" can all change the result. Do not stop a prescribed medication on your own; the provider will say what, if anything, to pause.
A lab needs an order from a licensed clinician. The free consult is where that order comes from, and it is also where the provider decides which of the labs above you need so you are not drawn twice.
If you want to know whether a test makes sense before you book anything, the two-minute symptom check covers the questions the provider asks first. If you are ready to talk, book a free TRT consultation and the labs are ordered from there. Our hormone therapy page explains the program the results might lead to, and the provider decides whether it is right for you.
Written by: Contour Medical Clinic Editorial Team