Clinic Compass

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Guide · United States

Bloodwork to ask for

Walk-in clinicians will run tests you ask for by name if the request is reasonable. Below is what to ask for, when, and why. Use the country switch below to see guidance tailored to Canada or the US.

Evidence strength
Guideline-recommended
A guideline body gives this a graded recommendation for someone with your profile.
Shared decision — worth discussing
Guidelines recommend deciding this together with a clinician rather than testing everyone.
Commonly ordered — evidence is mixed
No guideline body currently recommends this as routine screening for people without symptoms. It's still frequently ordered, and some clinicians and patients want it as a baseline — but the evidence that it improves outcomes is weak or absent. If you're paying cash, this is the group to think hardest about.

Complete Blood Count (CBC)

When there's a symptom to explain — no routine interval

Looks at red cells, white cells, and platelets. Useful when there's a symptom to explain — fatigue, heavy periods, easy bruising. Guidelines don't recommend it as a routine test in people without symptoms.

Ask for it like this

"Can I get a CBC with differential? I don't have a family doctor tracking my baseline."

If they hesitate

"I'm asking because of [fatigue / heavy periods / dizziness]. If a CBC isn't warranted, can you note the symptom in my chart?"

Cost & coverage — United States
Covered with conditions — ask

Not a graded preventive service — usually billed to your deductible. Ask for the cash price; a CBC is often $10–$30 at a direct-pay lab.

Set your state for a more specific note.

Expect your results: Usually back in 1–3 days.

Sources

Comprehensive Metabolic Panel (CMP)

When there's something to investigate — no routine interval

Measures kidney and liver function, blood sugar, and electrolytes. Standard when something needs investigating or a medication needs monitoring; not recommended as a routine test in people without symptoms.

Ask for it like this

"I'd like a CMP — kidney function, liver enzymes, electrolytes, and glucose."

If they hesitate

"If a CMP isn't indicated for me right now, what would make it worth doing — a medication, a symptom, or an age threshold?"

Cost & coverage — United States
Covered with conditions — ask

Usually billed as diagnostic. Cash price at a direct-pay lab is typically $15–$40.

Set your state for a more specific note.

Expect your results: Usually back in 1–3 days.

Sources

Lipid panel (cholesterol)

Every 4–6 years from 20; every 1–2 years from 40 or with risk factors

LDL is the strongest modifiable predictor of heart attack and stroke. Estrogen therapy can shift lipid profile — worth tracking.

Ask for it like this

"Please order a fasting lipid panel — total, LDL, HDL, and triglycerides."

If they hesitate

"I've never had a lipid panel done. USPSTF and the Canadian Task Force both use cholesterol to estimate cardiovascular risk — can we establish a baseline?"

Cost & coverage — United States
Usually no cost to you

USPSTF-graded preventive screening — insured plans must cover it at no cost when coded as screening. Confirm the coding before the draw.

Set your state for a more specific note.

Expect your results: Usually back in 1–3 days.

Sources

Hemoglobin A1c (diabetes screen)

Every 3 years from 35; annually if overweight or family history

Detects diabetes years before symptoms; A1c reflects 3 months of blood sugar.

Ask for it like this

"I'd like an A1c to screen for prediabetes and diabetes."

If they hesitate

"Can we check A1c rather than fasting glucose? I can't reliably come back fasting without a regular doctor."

Cost & coverage — United States
Usually no cost to you

Diabetes screening is a graded preventive service for adults 35–70 with overweight/obesity — no cost-sharing on ACA plans.

Set your state for a more specific note.

Expect your results: Usually back in 1–3 days.

Sources

TSH (thyroid)

When symptoms point to the thyroid — no routine interval

Measures thyroid function. Worth doing when there are symptoms that fit — fatigue, weight or mood changes, cold intolerance. USPSTF and AAFP both advise against screening people without symptoms.

Ask for it like this

"Can we check my TSH? Fatigue, weight changes, and mood can all trace back to thyroid."

If they hesitate

"My symptoms overlap with thyroid — if TSH isn't indicated, what would you check instead?"

Cost & coverage — United States
Covered with conditions — ask

Not a graded screening test — likely billed. Cash price is usually $20–$40.

Set your state for a more specific note.

Expect your results: Usually back in 1–3 days.

Sources

Vitamin D (25-OH)

When there's a specific reason to check — no routine interval

Measures 25-hydroxy vitamin D. Low levels are common, but USPSTF found that treating deficiency picked up by screening didn't improve outcomes in people without symptoms — which is why it isn't recommended as a routine test.

Ask for it like this

"Can we check my 25-hydroxy vitamin D level?"

If they hesitate

"I've read that screening isn't routinely recommended. Is there anything in my history — bone pain, muscle weakness, a malabsorption condition, or a medication — that would make testing worthwhile for me?"

Cost & coverage — United States
Often out of pocket — ask the price

Not recommended as routine screening, so rarely covered. Cash price is typically $40–$70.

Set your state for a more specific note.

Expect your results: Usually back in 3–7 days — often sent to a reference lab.

Sources

Vitamin B12

When diet, medication or symptoms suggest a reason to check; recheck if a low level is being monitored

Measures vitamin B12. Worth testing when there's a recognized depletion risk — a plant-based diet, metformin, older age with symptoms, or an absorption problem. Not recommended as a routine test otherwise.

Ask for it like this

"Please add a B12 level."

If they hesitate

"I follow a plant-based diet / take metformin, which are both recognized B12 depletion risks."

Expect your results: Usually back in 2–5 days.

Sources

Ferritin (iron stores)

When fatigue, heavy periods or low hemoglobin suggest a reason to check; recheck if low iron is being monitored

Measures iron stores. Useful when there's fatigue, heavy periods, or a low hemoglobin to explain. No guideline recommends it as a routine test at a set interval in people without symptoms.

Ask for it like this

"Can we add a ferritin to check my iron stores?"

If they hesitate

"Hemoglobin can be normal while iron stores are low. Can we add ferritin to the same draw?"

Cost & coverage — United States
Covered with conditions — ask

Covered when there's a documented reason such as anemia or fatigue.

Set your state for a more specific note.

Expect your results: Usually back in 1–3 days.

Sources

PSA (prostate)

Discuss at 50 (45 if Black or family history), every 2 years if screening

Shared-decision test; can find early prostate cancer but also cause overtreatment. Long-term estrogen therapy lowers PSA — your clinician may interpret a 'normal' value differently.

Ask for it like this

"I'd like to discuss PSA testing — pros, cons, and whether it's right for me."

If they hesitate

"I know PSA is a shared-decision test. I'd like to make that decision — can we discuss it and note my choice in the chart?"

Cost & coverage — United States
Covered with conditions — ask

Shared-decision screening for ages 55–69 is generally covered; outside that range it may be billed.

Set your state for a more specific note.

Expect your results: Usually back in 1–3 days.

Sources

Hepatitis C (one-time)

Once between 18 and 79

Curable with 8–12 weeks of pills — but silent for decades if untreated.

Ask for it like this

"Have I ever been screened for Hepatitis C? I'd like the one-time test."

If they hesitate

"One-time hepatitis C screening is recommended for all adults — it's a single test, and treatment is curative."

Cost & coverage — United States
Usually no cost to you

One-time hepatitis C screening for adults is a graded preventive service.

Set your state for a more specific note.

Expect your results: Usually 3–7 days. A positive antibody test needs a second confirmatory test, which adds time.

Sources

Hemoglobinopathy screen (sickle cell & thalassemia)

Once as an adult if never done, or before pregnancy

Sickle cell and thalassemia carrier states are more common in people of African, Mediterranean, Middle Eastern, South/Southeast Asian, and Hispanic ancestry. Knowing your carrier status matters for anemia workups, surgical planning, and reproductive decisions.

Ask for it like this

"I have ancestry linked to hemoglobin disorders. Can we order a CBC plus hemoglobin electrophoresis (or HPLC) to check for sickle cell trait and thalassemia?"

If they hesitate

"This is ancestry-based screening that's standard in many prenatal and pre-conception guidelines — can we do the hemoglobin electrophoresis?"

Sources

G6PD deficiency test

Once — before starting any oxidative medication

G6PD deficiency is more common in people of African, Mediterranean, Middle Eastern, and South/Southeast Asian ancestry. Knowing your status prevents dangerous hemolysis from common medications and even fava beans.

Ask for it like this

"Given my ancestry, can we check a G6PD level before I'm ever prescribed antimalarials, sulfa drugs, or nitrofurantoin?"

If they hesitate

"Knowing my G6PD status changes which medications are safe for me. That's the reason for the test."

Sources

Hepatitis B screening (ancestry-based)

Once — repeat if ongoing exposure risk

Hepatitis B is more prevalent in people born in East Asia, Southeast Asia, the Pacific Islands, sub-Saharan Africa, and parts of Eastern Europe. It's silent for decades and now has excellent treatment.

Ask for it like this

"Please screen me for Hepatitis B (HBsAg, anti-HBs, anti-HBc). CDC recommends it for adults born in regions with higher prevalence."

If they hesitate

"Chronic hepatitis B is often silent, and CDC recommends screening for people born in higher-prevalence regions."

Sources

Hepatitis B & C status check

At diagnosis and if ever re-exposed; vaccinate if not immune

Co-infection changes both treatment and monitoring, and hepatitis B vaccination is specifically recommended for people living with HIV who aren't already immune.

Ask for it like this

"I'm living with HIV — please confirm my hepatitis B status (HBsAg, anti-HBs, anti-HBc) and hepatitis C, and vaccinate me for hep B if I'm not immune."

If they hesitate

Ask: "What would make this test worth doing?" — then ask them to note in my chart that I requested it and it was deferred, and what symptom would change that.

Sources

This is not medical advice. Clinic Compass is an educational tool to help you prepare for a walk-in visit. It does not create a doctor–patient relationship, does not diagnose or treat any condition, and is not a substitute for the judgement of a licensed healthcare professional who knows your history. Never delay, avoid, or change medical care because of something you read here. In an emergency, call 911 or your local emergency number.

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