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My Blood Test Results Are Abnormal. What Should I Do Next?

You open your blood-test report.

One number is marked HIGH. Another has an L beside it. Maybe something is shown in red.

Your first thought may be: “Is something seriously wrong?”

Not necessarily.

Written by: AAMC Polyclinic Editorial Team

Adult reviewing an abnormal blood test result and wondering what to do next

Does an Abnormal Blood Test Mean I Have a Disease?

No. An abnormal result is a clue. It is not always a diagnosis.

Most blood reports show something called a reference range. This is the range the laboratory uses to help compare your result with results seen in many healthy people.

But healthy people can sometimes have results outside that range. And people with a health problem can sometimes have a result that still falls inside the range.

What Does H or L Mean on a Blood-Test Report?

Many laboratory reports use simple letters:

Seeing H or L tells you where the number sits compared with the laboratory's range. It does not tell you the full reason.

Why Can a Healthy Person Have an Abnormal Result?

Because the human body does not always fit perfectly inside a box. Reference ranges are built using results from groups of healthy people, and some healthy people will naturally fall a little outside the range.

Results can also be affected by things such as:

That is why one slightly abnormal result may sometimes need a second look rather than an immediate diagnosis.

Slightly Abnormal vs Very Abnormal: Is There a Difference?

Yes, but you should not try to judge this only from the colour or arrow on the report. A result just outside the reference range may mean something very different from a result that is far outside the expected range. How important it is also depends on:

The same-looking “high” mark can mean very different things on two different tests.

One Abnormal Result vs a Pattern of Results

For example, MedlinePlus explains that when liver-test results are abnormal, doctors look at the pattern across several related results rather than one number alone. This idea applies to many types of blood testing.

Doctors often look for patterns, not isolated numbers.

Can Different Labs Use Different Normal Ranges?

Yes. This is very important.

Different laboratories may use different testing methods, machines, units and reference ranges. MedlinePlus advises comparing your result with the reference range printed on your own report, not a random range you found online.

So if your report says “Normal range: X–Y”, use that range. Do not compare it with a screenshot from Google or another person's report.

Can I Compare Results From Two Different Labs?

Be careful.

The numbers may look similar, but the laboratories may use different methods or reference ranges. If you are following a result over time, using the same laboratory can sometimes make trends easier to understand.

The most useful thing is to bring both complete reports to your doctor.

Can Food or Fasting Change a Blood-Test Result?

Yes, for some tests.

Whether fasting matters depends on the test. Eating or drinking before certain tests can change the result, which is why you may sometimes be told not to eat for a certain number of hours. Other tests do not need fasting. MedlinePlus says following the preparation instructions can affect how accurate certain results are.

Can Medicines or Supplements Affect My Blood Results?

Yes.

Some medicines and supplements can change certain test results. That is why your doctor needs to know what you take. Bring a list of:

Can Exercise or Recent Illness Affect Blood Tests?

For some tests, yes. Hard exercise before testing can affect certain results, and some results can change during or shortly after illness. MedlinePlus notes, for example, that certain abnormal liver-test results can sometimes be temporary after illness and may later be repeated.

Your doctor may ask: When was the blood taken? Had you exercised? Were you fasting? Were you sick? What medicines were you taking?

That does not mean an abnormal result should simply be ignored. It means timing and context can help explain a result that does not make sense at first. Tell your doctor if you were recently sick.

Should I Repeat an Abnormal Blood Test?

Sometimes.

A doctor may repeat a test when:

But do not automatically repeat every abnormal test yourself. First ask:

Why was it abnormal, and would repeating it help?

Should I Get More Blood Tests?

Maybe. But an abnormal result does not automatically mean “test everything.”

A doctor may instead decide to:

Blood tests do not always provide enough information on their own. Other information or tests may sometimes be needed before a diagnosis can be made.

Related reading: Annual Health Check in Dubai: Which Tests Do You Actually Need?

What Should I Check Before I Panic?

Use this simple checklist.

  1. 01Which test is abnormal?
    Write down the exact name.
  2. 02Is it high or low?
    Check the H, L or arrow.
  3. 03How does it compare with the lab's range?
    Use the range on your report.
  4. 04Was this test abnormal before?
    Look at older reports.
  5. 05Do you have symptoms?
    Tell the doctor what you are actually feeling.
  6. 06Were you fasting if required?
    Check the instructions.
  7. 07Were you sick recently?
    Mention it.
  8. 08Have your medicines changed?
    Bring the list.
  9. 09Has your doctor reviewed the result?
    If not, arrange a review.

This gives the doctor far more useful information than simply saying: “One number is red.”

Should I Google My Abnormal Blood Result?

It is fine to learn what a test measures. But be careful about diagnosing yourself. Searching “High ALT” or “Low haemoglobin” can produce a long list of diseases. That does not mean you have them.

One result needs to be read with other results, symptoms, medicines, medical history and previous tests.

The internet can explain what a test is. Your doctor needs to explain what your result may mean for you.

Should I Use an AI Tool to Explain My Blood Results?

AI can help explain difficult medical words in simpler language. But it should not replace a medical review when a result is abnormal or unclear. An AI tool may not know:

Common Types of Abnormal Results

You may see abnormal numbers in several areas.

Do not use this table to diagnose yourself. The meaning of each result is different.

What If My Blood Sugar Result Is High?

A high blood sugar result deserves proper review. But one number may not tell the full story. The doctor may look at:

Do not assume one high glucose result automatically means diabetes. The doctor may need more information.

Related AAMC service: Internal Medicine in Business Bay

What If My Cholesterol Is High?

High cholesterol is usually looked at as part of your wider heart-health risk. Your doctor may consider your age, blood pressure, smoking, diabetes, family history, other cholesterol results and other health conditions.

One cholesterol number does not tell the whole story.

The result should be discussed in context.

What If My TSH or Thyroid Result Is Abnormal?

An abnormal TSH can be an important clue about thyroid function. But TSH should not always be read alone. Depending on the result, a doctor may also consider T4, sometimes T3, thyroid antibodies, symptoms, medicines and previous thyroid tests. Where thyroid or hormone questions are the main concern, Hormone Health in Dubai may be relevant.

Related reading: TSH, T3 and T4 Explained

What If My Liver Test Is High?

Do not assume that one high liver result means you have liver disease. MedlinePlus explains that abnormal liver-test results can have different causes, and doctors usually look at the pattern across several results, along with symptoms, medicines and medical history. Sometimes a test may also be repeated if the change could be temporary.

Bring the complete report rather than one screenshot.

What If My Blood Count Is Abnormal?

A complete blood count looks at different blood cells, which may include red blood cells, white blood cells, platelets and haemoglobin. An abnormal result can have many possible causes. A doctor may look at:

A single abnormal blood-count result usually needs context before anyone can say what it means. If tiredness is part of the picture, see What Blood Tests Might a Doctor Consider for Persistent Fatigue?

What If I Feel Fine but My Blood Test Is Abnormal?

This happens. Some health problems can appear in blood results before you notice symptoms. But sometimes a small abnormal result is not a sign of serious disease.

That is why the next step is not ignore it, and not panic.

It is: review it.

The doctor can decide whether it needs no action, monitoring, repeat testing, another test, treatment or further review.

What If I Feel Unwell but My Results Are Only Slightly Abnormal?

Your symptoms still matter. A doctor should not look only at how far a number sits outside the reference range. The medical question is:

Does the result help explain what you are experiencing?

Sometimes it will. Sometimes it will not. That is why symptoms and test results need to be looked at together. If ongoing tiredness continues even when results look normal, see My Blood Tests Are Normal, So Why Am I Still Tired? or our Fatigue Assessment.

When Is an Abnormal Blood Result Urgent?

There is no single rule because blood tests measure many different things. Some results need quick medical attention. Others can wait for a normal follow-up visit. The urgency depends on which test is abnormal, how abnormal it is, your symptoms, your medical history and other test results.

If your clinic or laboratory tells you that a result needs urgent medical review, follow those instructions.

Who Should Review Several Abnormal Blood Results Together?

If several results are abnormal or you do not know which area of medicine they belong to, Internal Medicine can be a useful starting point for an adult.

AAMC's clinical focus includes adults with abnormal results, ongoing symptoms and test reports that need explanation. Dr. Jose Lopez can review symptoms, current medicines, medical history and previous reports together before deciding what needs attention next.

This is useful when your report does not fit neatly into one area. For example, blood sugar + cholesterol + weight, or fatigue + thyroid result + low iron result, may make more sense when looked at together.

Abnormal Result vs Results Review

The goal is not simply to make every number fall inside a box.

The goal is to understand what the numbers mean for your health.

What Should I Bring to a Blood-Test Results Review?

Do not bring only one screenshot if you have the full report. Related results may matter.

What Questions Should I Ask the Doctor?

This gives you a much clearer appointment than simply asking: “Are my blood tests bad?”

What Happens at AAMC if You Have Abnormal Blood-Test Results?

Abnormal test results and reports that need explanation are among the reasons adults may start with Internal Medicine at AAMC. At a review, the useful starting point is to bring together:

Dr. Jose Lopez can then review the wider picture before deciding what the next useful step may be. That may mean monitoring, further testing, medication review, follow-up or another type of care when appropriate.

Related AAMC service: Internal Medicine in Business Bay

If you are thinking about preventive screening rather than a specific result, see our Health Check in Business Bay.

Quick Guide: What Should You Do Next?

The Bottom Line

An abnormal blood-test result can feel worrying. But a result marked high, low or abnormal does not automatically mean you have a serious disease. The useful questions are:

MedlinePlus recommends looking at lab results together with other information about your health instead of using one number alone.

Have Blood-Test Results You Do Not Understand?

Bring the complete report and review the results in the context of your wider health.

Book an Internal Medicine Consultation

Book With Dr. Jose Lopez

Ask AAMC on WhatsApp

Frequently Asked Questions

Does an abnormal blood test mean something is wrong?

Not always. Healthy people can sometimes have results outside a laboratory's reference range. Your doctor needs to look at the result with your symptoms, medical history and other tests.

Why is one of my results marked H or L?

H usually means the result is above that laboratory's reference range. L usually means it is below the range. This does not tell you the cause by itself.

Can two labs give different normal ranges?

Yes. Laboratories may use different methods and reference ranges. Use the range printed on your own report when looking at your result.

Can medicines affect blood-test results?

Yes. Medicines, vitamins and supplements can affect some results. Tell your healthcare provider what you take and do not stop prescribed medicine without medical advice.

Can food affect blood-test results?

Yes, some tests can be affected by food or drink. Follow the preparation and fasting instructions given for your specific test.

Should an abnormal blood test be repeated?

Sometimes. A doctor may repeat a test if the result is unexpected, may have been affected by another factor, or needs confirmation.

Should I worry about one result being slightly outside the normal range?

Not automatically. One slightly high or low result may not mean you have a health problem. The test, symptoms and other results all matter.

Which doctor can explain several abnormal blood-test results?

For an adult with several results, symptoms or health concerns that overlap, Internal Medicine can be a practical starting point. AAMC specifically includes abnormal test results and reports that need explanation within its Internal Medicine focus.

Related Reading

Medical References

  1. MedlinePlus – How to Understand Your Lab Results
  2. MedlinePlus – What You Need to Know About Blood Testing
  3. MedlinePlus – Laboratory Tests
  4. MedlinePlus – Liver Function Tests
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