Best At-Home Blood Tests Before Starting a GLP-1

Before you start a GLP-1 like semaglutide or tirzepatide, you need a short list of blood tests, not a giant panel. A clinical guide for prescribers in eClinicalMedicine calls baseline kidney and liver tests reasonable. It also suggests a triglyceride test if you have risk factors for pancreatitis, such as gallstones or very high triglycerides. Quest's $44.10 comprehensive metabolic panel covers kidney, liver and blood sugar, so a $365 to $399 longevity panel is optional. The thyroid check that matters before a GLP-1 is whether you or a close relative has had medullary thyroid cancer or MEN 2. You answer that from your family history, not with a blood draw.

Which blood tests do you need before starting a GLP-1?

• Kidney and liver function. These are the core baseline. The eClinicalMedicine guide calls them reasonable before you start. After that, it says retesting should follow how you are doing rather than a fixed schedule.
• Triglycerides, if you have risk factors. Add this test if you have had gallstones or know your triglycerides run high. The guide names these as risk factors for pancreatitis, a rare but serious inflammation of the pancreas linked to GLP-1s.
• A1c. This test measures your average blood sugar over the past 2 to 3 months. It gives you a starting number to compare against later on your plan.
• No routine thyroid blood test. The guide advises against routine thyroid screening or calcitonin tests before a GLP-1. What matters is whether you, a parent, a sibling or a child has had medullary thyroid cancer or MEN 2 (an inherited gland condition). Either one rules a GLP-1 out.
• Thyroid nodules, goiter or Hashimoto's do not rule you out. If you take levothyroxine, your clinical team may space it apart from your other medicines. They may also recheck your TSH (thyroid-stimulating hormone) after you start or raise your dose.
• Other peptides. If you are starting a different peptide, ask your clinical team which labs they want first. The right baseline depends on the treatment.

Are at-home finger-prick blood tests accurate?

For most routine markers, yes. A 2024 study compared finger-prick blood with blood drawn from an arm vein. Of the 33 markers with a set accuracy standard, 30 met it. The markers tested included liver enzymes, creatinine (a kidney marker) and triglycerides.

Glucose was the one marker that missed the stricter US lab standard. If you want a blood sugar result from a finger prick, rely on A1c rather than a single glucose reading.

A1c from a mailed finger-prick kit held up well. In a study of 122 adults aged 35 to 86, 96.7% of home results came within 0.2 percentage points of the arm-draw result. In the same study, 97% of those surveyed said the kit would be easy to do at home.

If needles put you off, you can choose a finger prick or a phlebotomist who comes to your home. Either way you get the same baseline without sitting in a lab waiting room.

Which at-home blood test service should I pick?

Quest's metabolic panel is the budget pick. To complete the baseline, add Quest's lipid panel for triglycerides and its A1c test, and check those prices at checkout. Function and Everlywell both include the GLP-1 baseline markers: liver enzymes (ALT and AST), creatinine, eGFR (an estimate of how well your kidneys filter), triglycerides and A1c.

Function and Everlywell do not offer prescriptions, and none of these services is set up to start a GLP-1 for you. Keep a copy of your results to share with your clinical team.

To pay, note that Quest does not bill insurance, but you may be able to use HSA or FSA funds. Function is HSA/FSA eligible.

If you choose the hormone panel, the timing of your draw matters. Quest asks for an 8 to 12 hour fast and prefers a morning draw. If you still get periods, it asks for a draw on day 2, 3 or 4 of your cycle.

What can blood work not tell you about starting a GLP-1?

Normal labs do not predict how the medicine will feel. One Zepbound user wrote, "All my labs look good. Gallbladder and pancreas look good." They still could not tolerate the starting dose, and they stopped. "The good in all this, I lost 23 lbs and I got really great at counting calories," they wrote. Their advice: "Listen to your body while it whispers, before it starts to yell."

The early weeks go more smoothly when you know which symptoms are common, which call for a simple dose change and which need urgent care. The eClinicalMedicine guide says patients who understand this stick with treatment better and feel more comfortable. You get that from a conversation with your clinical team, not from a lab result.

Once you start, the number to watch is your weight. The ADA 2026 Standards of Care, cited in the guide, check your results after 3 months on your highest comfortable dose. If you have lost at least 5% by then, you keep going long term. If you have lost less than 5%, your dose and how you are taking it get reviewed. Switching medicine, such as moving from semaglutide to tirzepatide, is a reasonable option at that point.

Our clinical team can prescribe semaglutide, tirzepatide or retatrutide if one fits your goal, and your baseline numbers give them a clear starting point. You want your jeans to fit again, and a $44.10 metabolic panel covers most of the baseline. Take the quiz to see whether semaglutide, tirzepatide or retatrutide fits your goal, and keep your lab results handy to share with your clinical team.