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Men's lab tests explained

What each marker measures, what moves it, what it means with your symptoms, and which panel includes it. Same-day draws in San Gabriel and Downey.

Preventative Blood Testing

  • ALT and AST liver enzymes ALT and AST are enzymes that leak into the blood when liver or muscle cells are stressed.
  • ApoB blood test ApoB, or apolipoprotein B, is a protein carried once by every LDL, VLDL and Lp(a) particle, so its level counts the particles that can lodge in artery walls.
  • Bioavailable testosterone test Bioavailable testosterone is the free testosterone in your blood plus the portion loosely attached to albumin, which tissues can also draw on.
  • Blood tests for fatigue in men A practical fatigue workup for men checks eight markers: a complete blood count, ferritin, TSH, vitamin B12, vitamin D, hemoglobin A1c, an early-morning testosterone and, when symptoms point that way, a morning cortisol.
  • CBC blood test A complete blood count (CBC) measures red cells, white cells and platelets, plus red-cell size and shape indices such as MCV and RDW.
  • Comprehensive metabolic panel (CMP) A comprehensive metabolic panel is a routine blood test that reports 14 values.
  • Creatine kinase (CK) test A creatine kinase (CK) test measures an enzyme that leaks out of muscle when it is strained or damaged.
  • Cystatin C test Cystatin C is a protein made by cells throughout the body, and healthy kidneys keep its blood level steady.
  • DHEA-S blood test for men A DHEA-S test measures dehydroepiandrosterone sulfate, a hormone made mostly by the adrenal glands.
  • eGFR and creatinine kidney test eGFR, the estimated glomerular filtration rate, is calculated from your blood creatinine, age and sex.
  • Fasting before a testosterone test Yes, it matters for diagnosis. In a study of 74 men, a standard glucose drink lowered average testosterone by 25%, and levels were still below baseline two hours later.
  • Ferritin blood test for men Ferritin is the protein that stores iron, and its blood level tracks your iron reserves.
  • Folate blood test A folate blood test measures folic acid, the B vitamin your bone marrow needs to build red blood cells.
  • Free PSA test A free PSA test measures how much of your PSA circulates unattached to blood proteins, reported as a percentage of total PSA.
  • Free T3 test A free T3 test measures the unbound form of triiodothyronine, the most active thyroid hormone.
  • Free T4 test A free T4 test measures the unbound thyroxine your thyroid releases, and it confirms or refines what a TSH result suggests.
  • Free testosterone calculator explained A free testosterone calculator estimates the small, unbound share of testosterone from three lab values, total testosterone, SHBG and albumin, using the equation Vermeulen published in 1999.
  • FSH test for men FSH, follicle-stimulating hormone, is the pituitary signal that tells the testes to make sperm.
  • GGT blood test A GGT test measures gamma-glutamyl transferase, an enzyme found mainly in the liver and bile ducts.
  • Hematocrit blood test for men Hematocrit is the share of your blood volume made up of red blood cells.
  • High ApoB with normal LDL Every artery-clogging lipoprotein particle carries exactly one ApoB molecule, so ApoB counts particles, while LDL cholesterol measures how much cholesterol they carry.
  • High bilirubin and Gilbert's syndrome When bilirubin is only mildly high, the raised part is the indirect (unconjugated) form, and liver enzymes are normal, the usual explanation is Gilbert's syndrome.
  • High estradiol in men not on TRT In men who are not on testosterone, a high estradiol usually traces back to excess body fat, heavy drinking, liver disease or a medicine, and less often to thyroid problems or a rare tumor.
  • High ferritin in men A high ferritin in a man usually reflects fatty liver, alcohol, inflammation or metabolic syndrome rather than too much iron.
  • High hematocrit before starting TRT A hematocrit above about 48% before treatment, or above 50% for men living at high altitude, is a relative reason not to start testosterone under the Endocrine Society guideline, because testosterone raises red cell counts further.
  • High liver enzymes after lifting A hard lifting session can raise AST and ALT, because muscle contains both enzymes.
  • High PSA before starting TRT Under the Endocrine Society guideline, testosterone should not be started in a man whose PSA is above 4 ng/mL, or above 3 ng/mL if he is at higher risk of prostate cancer, until a urological evaluation is done.
  • High TSH with normal free T4 A high TSH with a normal free T4 is called subclinical hypothyroidism.
  • HLA-B27 test HLA-B27 is an inherited immune marker linked to ankylosing spondylitis and related inflammatory arthritis.
  • Homocysteine blood test Homocysteine is an amino acid your body clears with vitamin B12, folate and vitamin B6, and levels under about 15 µmol/L are usually called normal.
  • hs-CRP blood test The high-sensitivity CRP (hs-CRP) test measures low-grade inflammation linked to heart disease risk.
  • Iron panel and transferrin saturation An iron panel measures serum iron, total iron-binding capacity (TIBC) or transferrin, and transferrin saturation, usually alongside ferritin.
  • LDL particle number (LDL-P) test An LDL-P test uses nuclear magnetic resonance (NMR) to count LDL particles, reported in nmol/L.
  • Lipid panel for men A lipid panel reports total cholesterol, LDL, HDL and triglycerides, and most men do not need to fast for it, because normal meals shift the results only slightly.
  • Lipoprotein(a) blood test Lipoprotein(a), or Lp(a), is an inherited cholesterol particle that raises the risk of heart attack, stroke and aortic valve narrowing.
  • Low hemoglobin in men Low hemoglobin, or anemia, in an adult man is never just a number to supplement away; it needs a cause.
  • Magnesium blood test A standard magnesium blood test measures serum magnesium, which holds well under 1 percent of the body's supply, so it can read normal while stores are low.
  • Morning cortisol test Cortisol peaks in the early morning and falls through the day, so the test is drawn around 8 a.m. to be readable.
  • Morning testosterone test timing Testosterone is highest in the early morning and falls through the day; in men aged 30 to 40 it can be 20 to 25% lower at 4 p.m. than at 8 a.m.
  • MTHFR gene test The MTHFR test checks two common variants, C677T and A1298C, that can slow how your body uses folate to clear homocysteine.
  • Omega-3 index test The omega-3 index measures EPA and DHA as a percentage of the fatty acids in your red blood cell membranes, which reflects your longer-term intake.
  • Prolactin test for men Prolactin is a pituitary hormone that, in men, normally runs under about 20 ng/mL.
  • PSA blood test for men PSA is a protein made by the prostate, and a blood test measures how much reaches the bloodstream.
  • PSA on finasteride Finasteride lowers PSA by roughly half; the Proscar label puts the drop at about 50%, and a trial of the 1 mg hair-loss dose found median drops of 40 to 50% within 48 weeks in men aged 40 to 60.
  • Reverse T3 test Usually not. Reverse T3 is an inactive form of thyroid hormone, and the American Thyroid Association says measuring it does not help diagnose hypothyroidism in healthy people outside the hospital.
  • SHBG blood test for men An SHBG blood test measures sex hormone binding globulin, a liver protein that holds testosterone tightly and keeps it away from your tissues.
  • Thyroid antibody test (TPO and TgAb) Thyroid antibody tests look for thyroid peroxidase (TPO) and thyroglobulin (TgAb) antibodies, the immune signature of Hashimoto's disease.
  • TSH test for men TSH is the pituitary signal that tells your thyroid how hard to work, and it is the usual first thyroid test.
  • Uric acid blood test A uric acid blood test measures urate, the waste left when your body breaks down purines.
  • Vitamin B12 blood test A serum B12 test measures vitamin B12 in your blood, but cutoffs vary by source.
  • Vitamin D blood test for men The vitamin D blood test measures 25-hydroxyvitamin D, the storage form your body builds from sun, food and supplements.
  • What can raise PSA temporarily PSA can rise for a short time after ejaculation, vigorous cycling, a prostate or urinary tract infection, a prostate biopsy, cystoscopy or a urinary catheter.
  • What can throw off a testosterone test A testosterone result can be pulled off course by things that have nothing to do with your hormones long term.
  • When should men start PSA screening? For average-risk men, the U.S. Preventive Services Task Force calls PSA screening an individual decision from 55 to 69, and the American Cancer Society starts the conversation at 50.
  • Zinc blood test A zinc blood test measures the zinc circulating in your serum or plasma.

Testosterone Therapy (TRT)

  • Blood tests for low libido in men A low libido workup starts with a morning total testosterone, then adds prolactin, estradiol, LH and often TSH.
  • Blood work after a steroid or SARM cycle After a steroid or SARM cycle, a useful panel checks LH, FSH and morning total testosterone to see whether your own production is restarting, plus estradiol, hematocrit, lipids and liver enzymes for the effects of the cycle itself.
  • Blood work after coming off TRT After stopping TRT, recovery is tracked with LH, FSH and early-morning total testosterone.
  • Borderline testosterone levels: 300 to 400 ng/dL A total testosterone of 300 to 400 ng/dL sits just above the 300 ng/dL cutoff the AUA uses, so it is a gray zone rather than a diagnosis.
  • Cholesterol changes on TRT At normal replacement levels, testosterone's effect on cholesterol is usually small, and the AUA calls the overall evidence uncertain.
  • Free testosterone test A free testosterone test measures the small fraction of testosterone that is not bound to proteins.
  • High SHBG with normal testosterone When SHBG is high, more of your testosterone is tightly bound and unavailable to tissues, so total testosterone can look normal while free testosterone is low.
  • How often to get blood work on TRT Guidelines call for labs before you start, testosterone and hematocrit about 3 to 6 months in, a PSA recheck within the first year, and then testosterone, hematocrit and PSA review every 6 to 12 months.
  • Lab monitoring on HCG HCG therapy is monitored with testosterone, a sensitive estradiol test and hematocrit, plus a semen analysis when fertility is the goal.
  • LH blood test for men Luteinizing hormone (LH) is the pituitary signal that tells the testes to make testosterone.
  • Low estradiol in men Men need a modest amount of estradiol for bone strength, body fat regulation and sexual function.
  • Low testosterone with low LH When testosterone is low and LH is low or inappropriately normal, the problem usually sits in the pituitary or hypothalamus rather than the testes.
  • Normal testosterone levels by age For healthy, non-obese men aged 19 to 39, the harmonized reference range for total testosterone is about 264 to 916 ng/dL.
  • Rising PSA on TRT A small PSA rise is common after starting testosterone, as the prostate responds to restored hormone levels.
  • Sensitive estradiol test for men A sensitive estradiol test measures estradiol by liquid chromatography-tandem mass spectrometry (LC/MS), which can accurately read the low levels found in men.
  • Target testosterone level on TRT Guidelines aim for the middle of the normal range on treatment, not the top.
  • Testosterone too high on TRT A testosterone result above the reference range on TRT is often a timing artifact, from blood drawn near a peak soon after a dose.
  • Total testosterone blood test A total testosterone test measures all the testosterone in your blood, bound and free.
  • When to draw labs on TRT: trough vs peak Draw timing depends on how you take testosterone. The Endocrine Society measures injections midway between doses and pellets at the end of the dosing interval, while the Kyzatrex label checks levels 3 to 5 hours after the morning capsule.
  • Why one low testosterone result is not enough Testosterone varies enough from one day to the next that a single result cannot diagnose low testosterone.

Medical Weight Loss for Men

  • Blood work before semaglutide or tirzepatide Before semaglutide or tirzepatide, the usual checks are A1c, kidney function, a lipid panel and liver enzymes, plus a direct question about medullary thyroid cancer or MEN 2 in you or your family.
  • Fasting glucose test A fasting glucose test measures blood sugar after at least eight hours without food.
  • Fasting insulin test A fasting insulin test measures how much insulin your pancreas releases to hold blood sugar steady overnight.
  • HbA1c test for men HbA1c measures the share of your hemoglobin coated with glucose, which reflects your average blood sugar over the past two to three months.
  • HOMA-IR insulin resistance score HOMA-IR estimates insulin resistance from one fasting blood draw.
  • Low HDL cholesterol in men For men, an HDL below 40 mg/dL is considered low. Low HDL rarely travels alone; paired with high triglycerides, it usually signals insulin resistance and excess abdominal fat.
  • Low SHBG in men SHBG is the protein that binds testosterone tightly in the blood.
  • Testosterone after weight loss: when to retest Meaningful weight loss usually raises testosterone. A meta-analysis found total testosterone rose about 2.9 nmol/L (roughly 83 ng/dL) with low-calorie diets and about 8.7 nmol/L (roughly 252 ng/dL) after bariatric surgery, with bigger gains in men who lost more.
  • Triglycerides blood test A triglycerides test measures the fat carried in your blood, usually after a 9 to 12 hour fast.

Peptide Therapy

  • Blood work before peptide therapy Before a growth-hormone-releasing peptide such as sermorelin or tesamorelin, blood work usually pairs a baseline IGF-1 with fasting glucose, A1c and lipids.
  • IGF-1 blood test for men An IGF-1 blood test measures insulin-like growth factor 1, the hormone made mainly in the liver in response to growth hormone.

Erectile Dysfunction Treatment

  • Blood tests for erectile dysfunction A standard ED blood workup checks a morning total testosterone, a fasting glucose or A1c, a fasting lipid panel and kidney function, with thyroid tests and PSA added for some men.

Hair Restoration (PRP)

IV Therapy

  • Blood work before IV therapy It depends on what goes in the bag and how often. Before high-dose vitamin C, kidney function and a G6PD test matter, because the kidneys clear every gram and G6PD deficiency can trigger red cell breakdown.

Sermorelin

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