Lab Results & Blood Test Guides
Blood tests are one of the most common ways to check what is happening inside your body, but the results usually arrive as a column of abbreviations and numbers with almost no explanation attached. These guides and interpreters translate those numbers into plain English, so you can walk into your next appointment understanding what was measured and what the figures broadly mean.
Nothing here diagnoses anything. Interpreting a result properly means considering your symptoms, medical history, medication and previous results together — which is your doctor's job, not a calculator's. What these tools can do is help you ask better questions.
Interpret a specific result
Enter your value and see how it compares against recognised clinical reference ranges.
TSH Level Interpreter
Understand where your thyroid-stimulating hormone (TSH) result falls within general reference ranges.
Vitamin D Level Interpreter
Understand where your vitamin D blood result falls within general reference ranges.
Liver Enzyme (ALT) Interpreter
Understand where your ALT liver enzyme result falls within general reference ranges.
Haemoglobin Level Interpreter
Understand where your haemoglobin result falls within general reference ranges for anaemia screening.
Blood Sugar Interpreter
Understand your blood sugar test result for fasting, random, post-meal and HbA1c.
HbA1c to Average Glucose Converter
Convert your HbA1c percentage to estimated average blood glucose (eAG), or work backwards from your average glucose to HbA1c. Shows results in both mmol/L and mg/dL.
In-depth guides
Longer, medically-reviewed explanations of what blood tests measure and why.
How to read a lab report
Every value comes with a reference range
Next to each result your report prints a reference range — the span of values seen in most healthy people. A result inside that range is described as normal, and one outside it is usually flagged with an H for high or an L for low. That flag is a prompt to look closer, not a diagnosis. Reference ranges are typically set so that around 95 percent of healthy people fall inside them, which means roughly one healthy person in twenty will sit slightly outside a given range while being perfectly well.
Ranges differ between laboratories
Two labs can report the same sample as normal and abnormal, because each sets its ranges from its own analysers, methods and local population. This is why you should always compare a result against the range printed on your own report rather than one you found online. Our interpreters use widely recognised international ranges as a general guide; where your laboratory differs, your laboratory is the one that applies to you.
Check the units before anything else
A number without its unit is meaningless. Blood glucose, for instance, is reported in mmol/L in much of the world and mg/dL elsewhere, and the same reading expressed in the wrong unit can look alarming or reassuring when it is neither. Cholesterol, creatinine and vitamin D all have the same problem. Before comparing your result to anything, find the unit printed beside it and make sure it matches.
A trend tells you more than a single result
One value is a snapshot taken on one morning, and it can be shifted by recent illness, dehydration, exercise, fasting, pregnancy, the time of day and medication. A pattern across several tests over months is far more informative than any single figure. If you have older results, bring them to your appointment — the direction of travel is often the most useful thing in the file.
When to speak to a doctor
Contact a healthcare professional if a result is markedly outside its range, if you have symptoms alongside an abnormal value, if a previously stable result has moved substantially, or if you simply do not understand what you have been given. Never start, stop or change a medication on the basis of a result you have interpreted yourself.
Important: these guides and tools provide educational information only and are not a substitute for professional medical advice, diagnosis or treatment. Always discuss your results with a qualified healthcare provider. See our medical disclaimer and review process.