What each panel measures, which conditions it is used for, how a blood draw actually works, and what you should expect to pay.
A thyroid panel usually reports three things: TSH, a signal from your pituitary gland, and T4 and T3, the two hormones the thyroid actually makes. TSH tells the thyroid how hard to work, so it often shifts before the hormone levels do. Read together, the three numbers show whether the gland and its control signal are in step.
Five blood tests are frequently described as a general "baseline" health check: a complete blood count (CBC), a comprehensive metabolic panel (CMP), a lipid panel, hemoglobin A1c, and a thyroid-stimulating hormone (TSH) test. Together they survey blood cells, organ chemistry, cholesterol, blood sugar, and thyroid function. This article explains what each one measures. It is educational and not a recommendation about your own care.
You can order most routine blood tests online without seeing a doctor first. The ordering service has a physician sign the lab order for you, you have blood drawn at a Quest or LabCorp location, and the results come straight to you. New York, New Jersey and Rhode Island are the states these services most often exclude.
Testosterone replacement therapy (TRT) often lowers sperm production, because testosterone from outside the body tells the pituitary gland to cut back on LH and FSH, the two signals the testicles need to make sperm. The measurements used to follow this are a semen analysis, which is the direct measure, plus blood levels of LH, FSH, testosterone, estradiol and prolactin.
A semen analysis measures the volume of a semen sample and the number, movement and shape of the sperm in it. It is the main lab test for male fertility, and it is not a blood test: the sample is collected at a clinic or lab, or at home and delivered within 30 to 60 minutes. Blood-test ordering services don’t sell it, but they do sell the hormone tests often ordered alongside it.
The blood tests most often discussed in bodybuilding and strength communities fall into four groups: hormones (total and free testosterone, estradiol, SHBG, LH and FSH), general health panels (CBC and CMP), heart and metabolic markers (lipid panel, ApoB, A1c, fasting insulin), and thyroid, iron and vitamin markers. Hard training changes some of these numbers by itself, which matters when comparing results over time.
No single blood test diagnoses an autoimmune condition. Testing usually combines broad markers, such as an ANA test, CRP or ESR and a complete blood count, with antibody tests aimed at one organ, like thyroid peroxidase antibodies for the thyroid. Which tests make sense depends on symptoms, so the choice sits with a clinician.
You can order most routine blood tests yourself, without a doctor’s visit and without insurance, through an online ordering service. You pay a fixed published price up front, receive a requisition, and have blood drawn at a Quest Diagnostics or LabCorp patient service center. The sample, the laboratory and the result are the same ones a doctor’s order would produce. Only the price and the paperwork differ.
A comprehensive metabolic panel (CMP) measures 14 substances in one blood sample to give a broad picture of kidney function, liver function, blood sugar, protein levels and electrolyte balance. It is one of the most commonly ordered blood tests in routine care, and it usually requires fasting because it includes glucose.
A lipid panel measures four things from a single blood sample: total cholesterol, LDL cholesterol, HDL cholesterol and triglycerides. It is the standard test for assessing cardiovascular risk, and it is one of the cheapest and most widely stocked tests in self-pay lab testing. Interpreting the numbers is a job for a clinician who knows your history.
Most blood tests do not require fasting. The ones that usually do are glucose and insulin tests, and any panel containing them, such as a comprehensive metabolic panel. When fasting is required it normally means 8 to 12 hours with nothing but plain water. Always follow the instruction printed on your own requisition, because it is specific to the test that was ordered.
A routine blood draw takes about five minutes and collects one to a few small tubes, usually 10 to 30 mL in total, a fraction of what a blood donation takes. A phlebotomist finds a vein in the crook of your elbow, fills the tubes the requisition calls for, and sends them to the laboratory. The draw is identical no matter which service you ordered the test through.