Blood test check-ups: what they are and how to choose one

"I would like a full check-up, but I have no idea which blood tests to ask for." It is one of the questions we hear most often. The honest answer is that no single blood test check-up suits everyone. A useful check-up is a short list of tests, each with a reason behind it: your age, your sex at birth, your family history, the way you live and anything you have noticed in your body. This guide explains what a blood test check-up is, how to choose one and what the markers on the report mean.

What a blood test check-up is

A blood test check-up is a set of tests run on one sample, chosen to show how some parts of the body are working: blood sugar, cholesterol, liver, kidneys, iron, vitamins and, when there is a reason, hormones. Many of the things it looks at give no symptoms at first. The NHS notes that high cholesterol does not usually cause symptoms and that there are usually no symptoms of kidney disease in the early stages.

A check-up is not a hunt for every possible problem. A Cochrane review of general health checks in adults, covering more than 250,000 people in randomised trials, found that offering broad checks to everyone had little or no effect on overall deaths (Krogsbøll et al., 2019). That is a good reason to choose tests with a purpose rather than the longest list on offer. A result is most useful when you know why you asked for it and what you will do with it.

Feeling well or having symptoms: two different routes

If you feel well and want to know your numbers, a check-up gives you a baseline: a first set of results to compare with later. If you have a new or worrying symptom, a check-up is not the right first step. Book an appointment with your GP, who can examine you and decide which tests you need.

Some signs need help straight away:

• Call 999 for chest pain, sudden weakness or numbness on one side of the body, slurred speech, severe breathlessness or heavy bleeding.
• Call NHS 111 when you need urgent advice and it is not an emergency.

How to choose a blood test check-up

By age

In your 20s and 30s, the first numbers are usually cholesterol, blood sugar, iron and vitamin D. From 40, the NHS Health Check looks at heart and circulation every 5 years in England, and many people add a fuller cholesterol profile or kidney and liver markers. From 60, kidneys, vitamin B12, vitamin D and bone health come more into view. Our articles on check-ups in your 20s and 30s, check-ups from 40 and check-ups from 60 go through each stage.

By sex

Sex at birth changes some priorities. Heavy periods and pregnancy are very common causes of low iron, and an underactive thyroid caused by Hashimoto's disease is most common in women, usually starting between 30 and 50 (NHS). Low iron can affect how you feel even before anaemia shows up (Pasricha et al., 2021). In men, cholesterol and blood sugar usually come first, testosterone only when there are symptoms, and the prostate specific antigen (PSA) test only after a conversation with your GP. Read more in women's health blood tests, men's health blood tests and prostate health and the PSA test. If you are trans, non-binary or take hormones, tell whoever reads your results, because hormones change what is expected.

By situation

Some situations point to particular tests: tiredness that does not lift, a vegan diet, hard training, planning a pregnancy, the menopause or a medicine taken long term. The check-up guide lets you search by situation or symptom and shows which tests usually make sense, with the reason for each. If you train a lot, blood tests for athletes covers iron, vitamin D and recovery.

By family history

Heart disease at a young age in a parent or sibling, inherited high cholesterol or type 2 diabetes in the family can all bring some tests forward. The NHS suggests asking your GP surgery for a cholesterol test if you have never had one and you are over 40, overweight, or high cholesterol or heart problems run in your family.

What a typical check-up includes

Most check-ups are built from a few blocks. You do not need all of them:

• Blood sugar: glycated haemoglobin (HbA1c), the average of the last 2 to 3 months.
• Cholesterol: total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL) and triglycerides.
• Liver: enzymes such as alanine aminotransferase (ALT) and gamma-glutamyl transferase (GGT).
• Kidneys: creatinine and the estimated glomerular filtration rate (eGFR).
• Blood and iron: haemoglobin in a full blood count, and ferritin for iron stores.
• Vitamins and thyroid: vitamin D, vitamin B12 and thyroid stimulating hormone (TSH), when there is a reason.

Profiles such as the general health profile and the heart health profile combine several of these in one sample. Each test page shows what it includes and how the sample is collected, and our partner laboratory analyses it.

What each marker means

• Glycated haemoglobin (HbA1c): shows the average amount of sugar in your blood over the past 2 to 3 months. It is used to check for and follow diabetes. More in the glossary.
• Total cholesterol: the total amount of cholesterol, a waxy substance the body needs. Too much can lead to plaque in the arteries. You might be asked not to eat for up to 12 hours before a cholesterol test, although most people do not need to fast (NHS). Glossary.
• LDL cholesterol: often called "bad" cholesterol; too much can build up in the walls of the arteries. Glossary.
• HDL cholesterol: often called "good" cholesterol, because it takes excess cholesterol back to the liver. A low level may mean a higher risk of heart disease. Glossary.
• Triglycerides: a type of fat the body uses for energy. Diet, weight, smoking and inactivity can push it up. Glossary.
• ALT and GGT: liver enzymes. They can rise when the liver is inflamed, with alcohol or with some medicines. ALT and GGT in the glossary.
• Creatinine and eGFR: creatinine is a waste product from the muscles that the kidneys filter; eGFR is calculated from it, with age and sex, to show how well the kidneys filter the blood. Glossary.
• Haemoglobin: the protein in red blood cells that carries oxygen. A low level can point to anaemia. Glossary.
• Ferritin: the body's iron store. Low ferritin may suggest iron deficiency; it can also rise with inflammation, so it is read alongside other results. Glossary.
• Vitamin D: helps the body absorb calcium and keep bones and muscles strong. It is made in the skin with sunlight, so it tends to fall in winter. Glossary.
• Vitamin B12: needed for red blood cells and healthy nerves. It comes mainly from animal foods, so it matters on a plant-based diet. Glossary.
• TSH: made by the pituitary gland to regulate the thyroid. Levels too high or too low can point to an underactive or overactive thyroid. Glossary.

The blood test glossary explains every abbreviation you are likely to see on a report.

Reference ranges vary; take your results to a doctor you trust, such as your GP.

Practical tips before you book

• Write down your reason. "I want a baseline", "I am always tired" or "my father had a heart attack at 50" each lead to a different list.
• Check what the NHS already offers you. If you are 40 to 74 in England with no existing heart, kidney or diabetes condition, you should be invited to a free NHS Health Check every 5 years.
• Read the preparation on the test page. Some tests ask for fasting or a morning sample; the page tells you.
• Think about timing. Vitamin D is most telling in late winter. A hard workout can change some muscle and inflammation markers for a few days.
• Mention medicines and supplements. Biotin, for example, can change some results.
• Keep your results. One result is a snapshot; a series shows a trend. See why repeating blood tests over time helps.

Frequently asked questions

Is a bigger check-up always better? Not necessarily. Every extra test adds another chance of a result just outside the range that turns out to mean nothing, and more follow-up appointments. A short list chosen for a reason usually tells you more.

Do I need a GP referral to order a check-up? No. You can order tests directly from our catalogue. It is still worth sharing the results with your GP, who knows your history and decides on any next step.

How often should I repeat a check-up? It depends on your age, your history and your earlier results. When a marker is being followed, a repeat every 6 to 12 months is common, but only when your GP or the health professional following you advises it.

Will you tell me what my result means? We explain what each marker measures, but we never interpret an individual result. That conversation belongs with your GP, who can put the number in the context of your health.

Next steps

Start with the check-up guide, or answer three quick questions in the guided check-up. The pages by age and situation, such as 18 to 29, women 40 to 59 and men 40 to 59, list the usual tests with the research behind them. You can order on the site or in the BPR app, and if anything is unclear, write to [email protected] or use the form on the site or the app.

This content is for information and education only and does not replace an assessment or treatment by a qualified health professional. Always talk to your GP or a health professional for individual advice.

References

1. Krogsbøll LT, Jørgensen KJ, Gøtzsche PC. Cochrane Database Syst Rev. 2019;1(1):CD009009. PMID 30699470
2. Pasricha SR, Tye-Din J, Muckenthaler MU, Swinkels DW. Lancet. 2021;397(10270):233-248. PMID 33285139
3. Blood tests - NHS. nhs.uk
4. NHS Health Check - NHS. nhs.uk
5. High cholesterol: getting tested - NHS. nhs.uk
6. Chronic kidney disease - NHS. nhs.uk
7. Iron deficiency anaemia - NHS. nhs.uk
8. Underactive thyroid (hypothyroidism) - NHS. nhs.uk