LABWhat blood tests should you get in your 30s?
In your twenties, a checkup is mostly a formality. Somewhere after 30 that changes. Cholesterol starts to creep up, blood sugar begins to matter, and the first "let's keep an eye on this" shows up on a results sheet.
The good news: the list of tests you actually need is short. Here it is in plain words, with how often to get each one, the extras worth asking about, and what your DNA can add.
The checklist for your 30s
| Test | What it checks | How often in your 30s | Who recommends it |
|---|---|---|---|
| Cholesterol panel | LDL ("bad"), HDL ("good"), triglycerides | Every 4 to 6 years | American Heart Association |
| Blood pressure | Pressure in your arteries | Every 3 to 5 years if normal; yearly if you're at risk, and yearly from 40 | US Preventive Services Task Force |
| Blood sugar (HbA1c or fasting glucose) | Your average blood sugar | From 35, every 3 years; earlier if you carry extra weight and have another risk factor | American Diabetes Association |
| Lp(a) | An inherited type of cholesterol particle | Once in a lifetime | National Lipid Association |
| Hepatitis C | A liver virus that can hide for years | Once, between 18 and 79 | US Preventive Services Task Force |
| HIV | The virus behind AIDS | At least once, between 15 and 65 | US Preventive Services Task Force |
Blood pressure isn't a blood test, but it belongs on the list: it takes a minute and catches one of the most common silent problems.
What do these tests actually tell you?
Cholesterol panel. LDL is the cholesterol that builds up in artery walls over decades; HDL helps clear it; triglycerides rise with sugar, alcohol and extra weight. Your 30s are when the slow climb starts, which is exactly why a baseline helps.
Blood sugar. HbA1c shows your average blood sugar over the past two to three months. It catches prediabetes years before any symptoms, when walking more and eating differently can still turn it around.
Lp(a). This one is mostly set by your genes and barely changes with diet or exercise, so one test is enough. A high level adds to heart risk on top of LDL. If yours is high, your doctor may watch your other numbers more closely, and your parents, siblings and children may want to test too.
Hepatitis C and HIV. Both can stay silent for years, and both are treatable today. One test settles the question.
Which extra tests are worth asking for?
Doctors often add these to a checkup. None is required for every healthy adult, but each makes sense in the right situation:
- Complete blood count and metabolic panel. A broad look at blood cells, kidneys, liver and salts. Often part of a yearly physical.
- Ferritin (iron stores). Worth it if you have heavy periods, feel tired for no clear reason, or eat little meat. Don't take iron without it: some people's bodies store iron too well.
- Vitamin B12. Worth it if you eat no or few animal foods, or take metformin or long-term stomach-acid medicine.
- Vitamin D. Many doctors add it, though experts don't advise routine testing for healthy adults. If you do test, late winter shows your lowest level.
- Thyroid (TSH). Worth it when there are symptoms, such as unexplained tiredness, weight change or feeling cold. Experts don't recommend it for everyone without symptoms.
What can your DNA add to the list?
Guidelines are written for the average person. Your DNA can point to the few tests that matter more for you. Some examples from the markers in your raw data:
- Versions that lean toward higher LDL or triglycerides make the cholesterol panel more worth keeping on schedule.
- Versions that lean toward lower vitamin D, B12 or iron make those tests worth doing once, to learn your level.
- A few versions make a test read differently, for example B12 reading low or HbA1c reading low, which is worth telling whoever reads your results.
In the Helisoma app, the Lab tests page puts this together: the tests guidelines recommend for your age and sex, then the ones your DNA adds, each with a note on why and how to prepare. Take the list to your next appointment.
How should you prepare?
- Most labs no longer need fasting for a cholesterol panel, but some still do. Ask when you book.
- Skip alcohol the day before, since it pushes triglycerides up.
- Reschedule ferritin if you're sick: infections push it up for a while.
- Bring your previous results, so changes are easy to spot.
How do you make sense of the results?
Ask your doctor first. Then, if you like, give your results to your own AI together with your DNA report and ask: "What's worth keeping an eye on, and what can I change before my next test?" It will explain each number in plain words and suggest questions for your next visit.
Sources
- US Preventive Services Task Force. Hypertension in adults: screening, 2021. uspreventiveservicestaskforce.org
- American Heart Association. How to get your cholesterol tested. heart.org
- American Diabetes Association. Diagnosis and classification of diabetes: Standards of Care in Diabetes, 2025. diabetesjournals.org
- Koschinsky ML, et al. A focused update to the 2019 NLA scientific statement on use of lipoprotein(a) in clinical practice. Journal of Clinical Lipidology, 2024. PubMed 38565461
- US Preventive Services Task Force. Hepatitis C virus infection in adolescents and adults: screening, 2020. uspreventiveservicestaskforce.org
- US Preventive Services Task Force. Human immunodeficiency virus (HIV) infection: screening, 2019. uspreventiveservicestaskforce.org
- Demay MB, et al. Vitamin D for the prevention of disease: an Endocrine Society clinical practice guideline, 2024. PubMed 38828931
- US Preventive Services Task Force. Thyroid dysfunction: screening, 2015. uspreventiveservicestaskforce.org
