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Pre-therapy lab checklist: what is usually drawn before a first GLP-1 prescription, and where each item comes from

A one-page baseline list for semaglutide or tirzepatide: the tests most prescribers order, the tests the labels specifically do not ask for, the questions that matter more than any lab, and a printable checklist builder that adapts to your stage and conditions.

By FormBlends editorial teamUpdated September 4, 2026Educational, not medical advice

Pre-visit lab checklist

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Your situation

You are being evaluated or have a first visit booked.

Tick anything that applies

Each one adds the labs or questions that the labels or guidelines attach to it. Nothing is stored.

Checklist for your visit (10 items)

Prepared 2026-09-04 for before a first prescription. Take it to the visit and ask; your prescriber decides what to order.

  1. Labs to ask about

    • Hemoglobin A1c, and a fasting glucose if one has not been done recently

      Establishes where glucose sits before therapy. The diagnostic cut points are under 5.7%, 5.7% to 6.4% and 6.5% or higher.

      Source: MedlinePlus: A1C test | Read more

    • Lipid panel (total, LDL, HDL, triglycerides)

      A baseline to compare against later. The ADA Standards include a lipid profile in the initial evaluation for people with diabetes.

      Source: American Diabetes Association, Standards of Care in Diabetes 2026 | Read more

    • Comprehensive metabolic panel: creatinine with eGFR, electrolytes, ALT and AST

      Kidney and liver function before starting give the numbers to compare against if you later become dehydrated or unwell.

      Source: American Diabetes Association, Standards of Care in Diabetes 2026 | Read more

    • Complete blood count, if your prescriber orders a baseline panel

      Not required by any GLP-1 label. A baseline hemoglobin matters later because anemia can distort A1c.

      Source: MedlinePlus: CBC blood test | Read more

  2. Questions for the visit

  3. Tests that are not routine (so you are not surprised when they are not ordered)

  4. Symptoms that change the plan (labs or imaging are done when these appear)

This is a list of things to ask about, built from the FDA labels for the approved products and from published guidelines. It is not a diagnosis, an order set or medical advice. Reference ranges vary by laboratory and interpretation belongs to your clinician. Compounded semaglutide and tirzepatide are not FDA approved and are not interchangeable with the brand products the labels describe.

This is the page to read before a first appointment. It lists what is usually drawn, says where each item comes from, and is honest about the fact that none of it is mandated by the drug labels. The tool underneath builds a version tailored to your situation that you can print.

The usual baseline panel

Tests commonly drawn before a first semaglutide or tirzepatide prescription. 'Basis' is where the practice comes from; no GLP-1 label mandates any of these.
TestWhy it is drawnBasis
Hemoglobin A1cSorts no diabetes, prediabetes, diabetes; sets the monitoring schedule; baseline for later comparisonADA initial evaluation; MedlinePlus cut points
Fasting glucoseCorroborates the A1c; free on a fasting CMP; sets the low end for people on insulin or a sulfonylureaADA; label hypoglycemia warnings
Lipid panelCardiovascular risk is part of the reason for treatment; baseline for later comparisonADA Section 10; Wegovy CV indication
Comprehensive metabolic panelKidney function and electrolytes (the labels' one re-check), liver enzymes, proteinsLabel section 5.5 (Wegovy) and equivalents; ADA
Complete blood countAnemia is common and makes A1c unreliable; baseline hemoglobinCommon practice; MedlinePlus A1c caveats
TSHOnly with thyroid history, levothyroxine or symptoms. Does not address the C-cell warningNot in any label; ATA guideline for those on levothyroxine
Vitamin B12With metformin, acid reducers, vegan diet, bariatric history or age over 50ADA (metformin); NIH ODS risk groups
FerritinWith heavy periods, low hemoglobin or MCV, restricted dietCommon practice; WHO thresholds
Pregnancy testCommonly requested before the first dose in anyone who could be pregnantNot label-mandated; labels say discontinue if pregnancy recognized

What is deliberately not on the list

Three tests get asked for and are not routine, and the sources are explicit.

Calcitonin and thyroid ultrasound. Each label says routine monitoring of serum calcitonin or thyroid ultrasound is of uncertain value for early detection of medullary thyroid carcinoma, and may lead to unnecessary procedures. The calcitonin page quotes the paragraph in full.

Lipase and amylase. The labels report that both rise on average in treated people and say the clinical significance of a rise without symptoms is unknown. They ask for symptom watch, not a schedule. See lipase and amylase.

Vitamin D. The 2024 Endocrine Society guideline suggests against routine 25-hydroxyvitamin D testing in healthy adults. Test with a reason (bone disease, malabsorption, treated deficiency), not by default. See vitamin D.

If any of these appears on your baseline, that is your prescriber's choice and gives a personal reference point. It is not something a label asked for, and a normal result should not be read as clearing the corresponding warning.

The questions that matter more than the labs

The labels' hard requirements are answers, not tests.

  • Personal or family history of medullary thyroid carcinoma or MEN 2. A contraindication in every label. Find out before the visit; "thyroid cancer" in a relative is usually a different type, and the prescriber needs to know which.
  • Insulin or a sulfonylurea on your medication list. Triggers the hypoglycemia warning and possibly a dose change.
  • Past pancreatitis. Not a contraindication, but the labels' pancreatitis warning makes it a first-visit topic.
  • Past gallstones or gallbladder surgery. Sets the symptom plan.
  • Diabetic retinopathy. The labels ask that people with a history of it be monitored for progression when glucose improves quickly; that is an eye exam, not a lab.
  • Contraception and pregnancy plans. The semaglutide two-month washout and the tirzepatide four-week oral contraceptive rule both start here.
  • Diuretics, ACE inhibitors, ARBs, SGLT2 inhibitors. These change how risky a dehydrated week is and are the reason to ask for a sick-day plan.
  • Whether the product is compounded. Compounded semaglutide and tirzepatide are not FDA approved and are not interchangeable with brand products; the labels quoted on this site describe the brand products.

Practical notes for the draw

Book it for the morning, fasting, so the glucose and lipids can be read as fasting values and the TSH (if drawn) is at its most consistent. Drink water. Take your usual medicines unless told otherwise. If you exercised hard the day before, mention it; AST and creatine kinase rise after heavy exertion. Ask for a copy of the report, or access to the portal, and keep it: the lab tracker exists so the baseline is still findable a year later.

Build your own list

The tool below takes your stage and conditions and produces a printable checklist of labs to ask about, questions for the visit, tests that are not routine, and symptoms that would change the plan. Every line carries its source. It does not diagnose anything and it does not tell your prescriber what to order.

For what happens after the baseline, see the monitoring calendar. For where a compounded program fits, the FormBlends GLP-1 overview describes theirs; the GLP-1 Starter site covers the first weeks in detail.

Questions people ask

If no label requires labs, why does my prescriber want them before starting?

Because a baseline turns every later result into information. The labels ask prescribers to monitor kidney function when someone becomes dehydrated, to watch glucose in people on insulin or a sulfonylurea, and to evaluate thyroid nodules and gallbladder symptoms. Each of those is easier with a before number. The ADA Standards also list these tests for the initial evaluation of anyone with diabetes. What the labels do not do is dictate the panel, which is why panels differ between prescribers.

What should I bring to the first visit besides the labs?

The list of everything you take, including supplements and acid reducers; your family history of thyroid cancer with as much detail as you can get; any history of pancreatitis, gallstones or kidney disease; your contraception; and, if you have them, recent results from another clinician so tests are not repeated. The checklist tool on this page turns those facts into the questions worth asking.

Canonical URL: https://formblendslabs.com/guides/pre-therapy-lab-checklist. Written by the FormBlends editorial team. This page is educational and is not medical advice; see the medical disclaimer.