How to Read a Blood Test Report: A Plain-English Guide

To read a blood test report, look at three things for each line: the result, the unit, and the reference range printed next to it. Results inside the range are usually considered typical; results marked H (high) or L (low) sit outside it. A single result slightly outside the range is common and rarely means something serious on its own.

If you'd like a second pair of eyes, paste your report into the free Blood Test Report Checker. It explains each marker in plain words and flags anything far outside the usual range. It runs entirely in your browser, so your results never leave your device.

What is on a typical blood test report?

Most reports are laid out as a table. Each row is one test, sometimes called a marker or analyte, and the columns usually are:

• Test name, often abbreviated: Hb or HGB for hemoglobin, TLC or WBC for white blood cells, SGPT for ALT, FBS for fasting blood sugar.
• Result, the number measured in your sample.
• Unit, such as g/dL, mg/dL, mmol/L or ×10³/µL. The same test can be reported in different units in different countries.
• Reference range (also called biological reference interval or normal range): the values seen in most healthy adults at that lab.
• Flag, usually H, L, High, Low, or an asterisk, added when a result falls outside the range.

Tests are grouped into panels. The most common are the complete blood count (CBC), blood sugar and HbA1c, the lipid profile, liver function tests (LFT), kidney function tests (KFT or RFT) and thyroid tests.

What does "normal range" really mean?

A reference range is usually built so that about 95 out of 100 healthy people fall inside it. That means roughly 1 in 20 healthy people will have a result just outside the range for any single test, with nothing wrong. The more tests on a report, the more likely it is that one or two are flagged by chance.

Ranges also differ between labs, and some depend on your age and sex. Hemoglobin, for example, has a lower typical range for women than for men. Always compare your result with the range on your own report first.

Some markers are judged against decision limits rather than a "normal" range. HbA1c, LDL cholesterol, vitamin D and eGFR use categories agreed by expert bodies (for example, an HbA1c of 5.7–6.4% is called the prediabetes range by the American Diabetes Association).

How do I read units like mg/dL and mmol/L?

Units matter because the same result looks very different in each system. A fasting glucose of 100 mg/dL is the same as 5.6 mmol/L. Total cholesterol of 200 mg/dL is about 5.2 mmol/L. Hemoglobin of 13.5 g/dL is 135 g/L.

Labs in South Asia often write white cells as "cells/cumm" and platelets in "lakh/cumm". 1.5 lakh/cumm platelets is the same as 150 ×10³/µL. The checker converts these common units for you, so you can paste a report as it is.

How do I check my report with the free tool?

1. Open the Blood Test Report Checker.
2. Under How to add your results, pick Paste report, Upload PDF or Enter values. Pasting works with text copied from a lab portal or email. Digital PDFs from the lab work best; scanned or photographed reports can't be read, so type those values in.
3. Set your sex and age. Some ranges depend on them, and kidney function (eGFR) is calculated from creatinine, age and sex.
4. Read Your results. Each test shows Normal, Borderline or Out of range, a bar showing where your value sits, what the test measures, possible reasons for a high or low value, and questions to ask your doctor.
5. Use Copy summary or print the page to take it to your appointment.

Try Try an example first if you want to see how it works before using your own report.

Which results should I look at first?

Start with anything your lab has flagged, then look at the big picture rather than single numbers:

• CBC: hemoglobin, white cells and platelets. See our guide to CBC results.
• Blood sugar: fasting glucose and HbA1c. See HbA1c and blood sugar levels explained.
• Cholesterol: LDL, HDL and triglycerides. See lipid profile results explained.
• Liver and kidney: ALT, AST, bilirubin, creatinine and eGFR. See the liver and kidney guides.

A pattern, such as low hemoglobin together with small red cells (low MCV), tells your doctor much more than one number does.

When should I contact a doctor urgently?

Some results are far enough outside the range that they need attention the same day, especially if you feel unwell. Examples include very low hemoglobin, very high or very low potassium or sodium, very low blood sugar, or a very low platelet count. The checker shows a clear warning when a value is in this zone. Labs also often phone the doctor directly about critical values.

If you have chest pain, trouble breathing, confusion, fainting or severe weakness, seek emergency care whatever the report says.

What a checker can and can't do

A checker is a learning tool, not a diagnosis. It doesn't know your medicines, pregnancy, recent illness, exercise or whether you were fasting, and all of these change results. Use it to understand the words on the page and prepare good questions, then go through the report with your doctor.

For everyday health, the BMI Calculator and the Food Calorie & Fiber Checker are useful companions. When you're ready, check your report now.