What blood tests should I get? A guide by age, risk and symptom

Guidelines name six tests for most adults: a lipid panel, a diabetes screen, one-time hepatitis B, hepatitis C and HIV tests, and Lp(a) once. Any test beyond those should have a reason that applies to you. The list comes from the US Preventive Services Task Force (USPSTF), the CDC, the American Heart Association and the European Atherosclerosis Society. This page lays it out with ages and intervals, then covers what to add for your situation, what usually is not needed and what a blood test cannot see.

The tests guidelines say most adults should have

Each guideline test has a stated starting age and repeat interval. The USPSTF gives an A or B grade to diabetes screening, hepatitis C screening and HIV screening, meaning there is good evidence that testing people without symptoms leads to better outcomes ¹. The CDC added universal hepatitis B screening for adults in 2023 ², and cholesterol testing is anchored in the AHA/ACC cholesterol guideline ³.

The intervals differ because the targets differ. Cholesterol and blood sugar drift with age and weight, so they are rechecked. Hepatitis B, hepatitis C and HIV are infections you either have or do not, so one negative test holds unless your risk changes. Lp(a), a cholesterol-carrying particle set mostly by your genes, barely moves across adult life, so the European Atherosclerosis Society advises measuring it at least once in every adult ⁴. The AHA/ACC guideline is narrower and treats Lp(a) as a test for selected people, such as those with a family history of early heart disease ³.

Diabetes screening has two US positions. The USPSTF recommends an A1C or glucose test for adults aged 35 to 70 who have overweight or obesity, repeated about every 3 years if normal ¹. The American Diabetes Association goes wider and screens every adult from 35. On an A1C, 5.7 to 6.4% marks prediabetes and 6.5% or above is in the diabetes range ⁵. If you are deciding between the two blood sugar tests, our A1C vs fasting glucose comparison sets them side by side, and the prediabetes page covers what a borderline result means.

Got a lipid panel back already? How to read your lipid panel walks through each line, and high cholesterol covers what a raised result means. If any core test comes back flagged, do not panic or order a bigger panel. Take it to your clinician, who can say whether to repeat it and which one extra test would answer the question.

The baseline panel: CBC and metabolic panel

A complete blood count (CBC) and a comprehensive metabolic panel (CMP) are the two tests most people picture when they hear "routine blood work". Neither has a USPSTF screening grade, but both are cheap, run on one tube each and give you a reference point for later. A comprehensive blood testing package sold online is usually these two plus extras.

• A CBC counts red cells, white cells and platelets. It can pick up anemia, signs of infection and some blood disorders. See the CBC explained.
• A CMP covers glucose, kidney markers (creatinine; eGFR, an estimate of how well your kidneys filter; BUN), liver enzymes, electrolytes, calcium and protein. See the metabolic panel explained.

A baseline earns its value later, when a new result can be compared with your own earlier one instead of a population range. Be realistic about the wider evidence, though. A Cochrane review of 17 trials covering about 250,000 people found that general health checks in adults did not reduce deaths from any cause, from heart disease or from cancer ⁶. So add tests for a reason, and do not run broad checks for reassurance.

General health checks are unlikely to be beneficial.Krogsbøll LT, Jørgensen KJ, Gøtzsche PC, Cochrane Database of Systematic Reviews 2019

Tests worth adding if this is you

An add-on test belongs on your list when something about you gives it a job. Each row below pairs a trigger with the test it justifies.

The ADA advises periodic vitamin B12 checks for people on long-term metformin ⁵. For PSA, the USPSTF rates screening at 55 to 69 as an individual decision and recommends against it from 70 ⁷. Kidney testing for people with diabetes or high blood pressure uses two numbers for a reason. KDIGO, the international kidney guideline group, defines chronic kidney disease as an eGFR below 60 or a urine albumin-to-creatinine ratio of 30 mg/g or more for over 3 months, so either one alone can miss early damage ⁸. If your blood pressure is part of the picture, our high blood pressure page explains the readings.

Usually not needed without a reason

Some popular tests have guidance against routine use in people who feel well. The Endocrine Society's 2024 guideline suggests against routine vitamin D testing in the general population without a specific indication ⁹, and the USPSTF found insufficient evidence to screen symptom-free adults for vitamin D deficiency ¹⁰. The USPSTF reached the same insufficient-evidence verdict on thyroid screening in non-pregnant adults without symptoms ¹¹. Both tests are reasonable when there is a reason, such as bone loss, malabsorption, fatigue with weight change or a pregnancy plan. A reason your clinician gives counts too.

By age and sex

For women, the most common add-on is ferritin with heavy periods, plus TSH and iron before a planned pregnancy. Hormone tests such as estradiol, FSH and progesterone only read correctly on the right cycle day, and hormonal birth control changes several results, so they should answer a specific question. Our blood tests for women guide, female hormone panel guide and birth control and blood tests go further. For men, testosterone belongs in a morning draw, and PSA is a choice to discuss between 55 and 69. If you train hard, blood tests for athletes covers the markers that move with training load.

Tests for a symptom you already have

A symptom changes the purpose of testing from screening to finding a cause, so the right tests come from the symptom. Each page below covers the tests in detail:

• Tiredness: CBC, ferritin, TSH, A1C and B12. See fatigue.
• Hair loss: ferritin and TSH first. See hair loss.
• Always cold: TSH and a CBC. See always cold.
• Low sex drive: testosterone, prolactin and TSH. See low libido.

Why more markers can mean more false alarms

A lab reference range is usually built to hold the middle 95% of healthy people, so about 1 healthy person in 20 lands outside it on any single test. Add more tests and those odds stack. Roughly, 5 tests give about a 1 in 4 chance of at least one flag, 10 tests about 2 in 5, and 20 tests nearly 2 in 3. Our reference ranges guide explains how the ranges are set.

Each flag on a healthy person tends to bring a repeat test, sometimes a scan and often some worry. Before adding a marker, ask four questions: what am I checking for, why does it apply to me, what would I do differently with the result, and when would a repeat help? If you cannot answer the third question, the test is unlikely to help you.

What a blood test cannot tell you

Standard blood work does not screen for most cancers. Tumor markers such as CEA or CA-125 are mainly used to track a cancer that has already been found; see tumor markers explained. A "full body" blood work panel also misses checks that need no needle at all: blood pressure, skin checks, and colon, breast and cervical screening. A blood pressure reading is the cheapest of these and needs no lab.

How often to repeat them

How often to repeat a test depends on why you ran it. Take any flagged result to the clinician who ordered it. A result far outside the range, or one the lab marks as critical, needs contact the same day, not a retest weeks later.

Compare repeats under the same conditions. Triglycerides move with your last meal, TSH and testosterone with the hour of the draw, and sex hormones with cycle day. Markers also affect each other: an underactive thyroid can raise LDL, and inflammation raises ferritin. One reading is a single point; two readings show a direction, which is why trends beat single readings.

How to get them done

In the US, most guideline screening tests are ordered at a preventive visit and are usually covered by insurance. Direct-to-consumer labs let you order tests yourself, usually by venous draw at a lab or a finger-prick kit at home. If you order your own tests, plan who will review a flagged result with you before you test. Finger-prick samples work for some markers, such as A1C, and are less reliable for others; see are at-home blood tests accurate and cheapest blood tests for the trade-offs.

Once you have results

A report with 30 lines and a handful of flags is easier to understand one line at a time, next to your own reason for testing. Bring any flagged result, and any decision about medicines or supplements, to the clinician who knows your history.

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