5 essential blood tests for adults: a clear baseline

Most people think about blood tests only when something feels wrong. But some of the most useful blood tests are not just about investigating symptoms. They can also help build a clearer picture of your health when you currently feel well.

That matters because many common health risks develop quietly. High cholesterol usually has no symptoms, but it can increase your risk of heart problems and stroke. Type 2 diabetes may develop gradually, and not everyone gets obvious symptoms. Kidney changes can also be picked up through routine blood or urine tests before they become obvious day to day.

A blood test is not a diagnosis on its own. It is a snapshot. The value comes from looking at the result in context: your age, health history, symptoms, lifestyle, blood pressure, body composition and any follow-up that may be needed.

Together, these are useful blood tests for overall health because they cover cardiovascular risk, blood sugar, organ function and blood cell patterns.

Here are five essential blood tests that can help give a clearer baseline picture of your health.

Cholesterol blood test

A cholesterol blood test, often called a lipid profile, looks at fats in your blood. This usually includes total cholesterol, HDL cholesterol, non-HDL cholesterol and triglycerides.

Cholesterol matters because too much cholesterol can build up in blood vessels and increase your risk of heart problems and stroke. High cholesterol does not usually cause symptoms, so a blood test is the only way to know if your level is raised.

A cholesterol blood test can be useful if you:

• Have a family history of heart disease or high cholesterol
• Have high blood pressure
• Smoke or used to smoke
• Are living with overweight or obesity
• Have type 2 diabetes or raised blood sugar
• Want a baseline before making lifestyle changes

The result doesn’t just tell you whether your cholesterol is “high” or “normal”. It can also show the pattern of cholesterol in your blood. For example, HDL is often described as “good” cholesterol because it helps remove other forms of cholesterol from the blood, while non-HDL cholesterol gives a broader picture of the cholesterol linked with cardiovascular risk.

If your cholesterol is raised, the next step may involve lifestyle changes, repeat testing, or a conversation with your GP about your wider cardiovascular risk. The result is one part of the picture, not the whole picture.

You can read more about this test on our cholesterol blood test page.

Diabetes blood test

A diabetes blood test looks at blood sugar. In private health screening, this commonly includes HbA1c, which gives an average picture of blood sugar over roughly the previous two to three months.

This is useful because type 2 diabetes often develops gradually. Some people have symptoms, such as thirst, tiredness, passing urine more often or blurred vision, but not everyone notices symptoms early.

A diabetes blood test can help show whether your blood sugar is in a healthy range, raised into a prediabetes range, or high enough to need medical follow-up. If a result suggests diabetes or prediabetes, diagnosis and ongoing management should be handled through your GP or diabetes care team.

This type of test can be especially useful if you:

• Have a family history of type 2 diabetes
• Have high blood pressure or raised cholesterol
• Are living with overweight or obesity
• Have a sedentary lifestyle
• Have had previous raised blood sugar
• Want to understand your metabolic health before making lifestyle changes

The key point is that blood sugar is modifiable for many people. A raised result can be the prompt to look at diet, activity, weight, sleep and GP follow-up before the issue becomes more serious.

You can read more on our diabetes blood test page.

Liver function blood test

A liver function blood test looks at markers linked with how the liver is working. These may include enzymes and proteins that can rise or fall when the liver is under strain.

Your liver is involved in hundreds of important processes, including processing alcohol, storing energy, making proteins and helping handle fats. Because it has a large reserve capacity, liver problems don’t always cause obvious symptoms early.

A liver blood test can help flag patterns that may be worth looking into, such as inflammation, alcohol-related strain, fatty liver risk, medication effects or other causes of liver stress. It doesn’t diagnose a specific condition by itself, but it can show when a follow-up conversation or repeat test may be sensible.

A liver function test may be useful if you:

• Drink alcohol regularly
• Have gained weight around the middle
• Have raised cholesterol or blood sugar
• Take medication that may affect the liver
• Have a family history of liver problems
• Want a broader health baseline

A mildly raised liver marker doesn’t automatically mean something serious is wrong. Results can be affected by alcohol, recent illness, medication, exercise and other factors. The important thing is to interpret the pattern properly and decide whether it needs repeating or discussing with your GP.

You can read more on our liver function test page.

Kidney function blood test

A kidney function blood test looks at how well your kidneys are filtering waste from your blood. One of the key markers is creatinine, which is used to estimate kidney filtering function, often reported as eGFR.

Kidney health is important because early kidney disease can have few or no symptoms. In many cases, kidney problems are found when a routine blood or urine test suggests the kidneys may not be working as expected.

A kidney function blood test may be useful if you:

• Have high blood pressure
• Have diabetes or raised blood sugar
• Have a family history of kidney disease
• Take medication that can affect kidney function
• Want a general health baseline
• Have previously had abnormal kidney markers

The result needs context. Kidney markers can be affected by age, muscle mass, hydration, recent exercise and other factors. A single abnormal result doesn’t always mean kidney disease, but it may justify repeat testing or GP follow-up.

Kidney function is one of the most useful areas to include in a general health check because it can pick up changes that are otherwise easy to miss.

You can read more on our kidney function blood test page.

Full blood count

A full blood count, often shortened to FBC, measures the number and types of cells in your blood. It looks at red blood cells, white blood cells and platelets.

This is one of the most commonly used blood tests because it gives a broad view of blood health. It can help flag patterns linked with iron deficiency anaemia, infection, inflammation, clotting issues or other blood-related concerns.

A full blood count can be useful if you:

• Feel tired or run down
• Have heavy periods
• Follow a restricted diet
• Have had recent illness
• Want a general baseline
• Have a previous history of anaemia or low iron

As with all blood tests, the result needs interpretation. A value slightly outside the reference range isn’t always a problem, and a normal result doesn’t rule out every possible condition. But as part of a wider health check, a full blood count is a useful foundation test.

You can read more on our full blood count page.

Why these five tests work well together

Each of these tests tells you something different.

• Cholesterol gives insight into cardiovascular risk.
• HbA1c and glucose help assess blood sugar and metabolic health.
• Liver markers can show whether the liver may be under strain.
• Kidney markers help assess filtering function.
• A full blood count gives a broad picture of blood cells and possible anaemia or infection patterns.

Together, they create a useful baseline. They don’t tell you everything about your health, but they cover several of the most important areas that can change quietly over time.

This is why these tests are often included in general health screening. They are practical, widely used and useful when interpreted alongside blood pressure, body composition, lifestyle and personal history.

What blood tests can’t tell you

Blood tests are useful, but they have limits.

They can’t see everything. A blood test isn’t imaging, so it can’t replace scans, X-rays or other investigations where those are needed.

They don’t diagnose every condition. Some results suggest a pattern that needs follow-up, but diagnosis usually requires your GP, repeat testing or further investigation.

They can produce false reassurance. A normal result today doesn’t mean nothing can change later.

They can also produce false alarms. A result outside the reference range may turn out to be temporary or not clinically significant when repeated.

That is why the interpretation matters as much as the test itself. A good health check shouldn’t just hand you numbers. It should explain what those numbers may mean, what they don’t mean, and what to do next if anything needs follow-up.

How these tests fit into an Essential Health Check

If you’re looking for private blood tests as part of a broader health check, the Essential Health Check is a sensible starting point. It’s designed as a focused baseline for adults who want a clearer picture of key health markers without jumping straight into a larger package.

It includes a broad set of blood tests and in-clinic checks to help assess areas such as cardiovascular risk, blood sugar, organ function and blood health. The aim isn’t to diagnose disease. The aim is to give you useful information, explain the results clearly and highlight anything that may need GP follow-up.

It may be a good fit if you:

• Have never had a private health check before
• Want a baseline in your thirties, forties, fifties or beyond
• Have a family history of heart disease, diabetes or other common conditions
• Want to check key markers before making lifestyle changes
• Feel well but want a structured health review

If you want a broader check, you can also compare our private health check packages, including the Advanced, Optimal, Men’s Cancer Marker and Women’s Cancer Marker Health Checks.

When to speak to your GP instead

A private blood test or health check is designed for adults who currently feel well and want to understand their health markers.

If you have symptoms that are worrying you, speak to your GP rather than booking a screening appointment. This includes symptoms such as chest pain, unexplained weight loss, a new lump, persistent changes in bowel habit, unexplained bleeding, severe tiredness or symptoms that are getting worse.

In a life-threatening emergency, call 999. For urgent advice that isn’t an emergency, NHS 111 is available online or by phone.

A useful baseline, not a final answer

The best way to think about these five blood tests is as a baseline. They help show where you are now. They can flag risks worth acting on. They can support better conversations with your GP if follow-up is needed.

They aren’t a verdict on your health. They are a starting point.

If you are considering a first private health check, the Essential Health Check is a sensible place to start. If you are unsure which package fits, contact us and we can help you choose the most appropriate option. Appointments are available from our Kingston upon Thames and Crawley clinics.