# How to read a lab report in seven steps

> Doctano turns the lab reports you already have into one private, source-linked health timeline, with an AI that answers from your own results.

Most confusion on a lab report comes from reading one number at a time. Read it in a fixed order and the page turns into a set of comparisons.

This is the Markdown version of https://doctano.com/guides/how-to-read-a-lab-report. The HTML page is the canonical version.

Read a lab report in this order: confirm whose report it is and when the sample was collected, find the full test name, read the value with its unit, read the reference range printed on that same report, check the flag and any remarks, then compare the value with your earlier results. Doctano does the last step by keeping every result on a timeline and linking each one to its source.

## Before you read a number

The first page of a lab report is mostly context, and four details tell you whether you are reading the right document.

- **Whose report it is.** The name and date of birth should match the person you are reading for.
- **When the sample was collected.** This is not always the same as the report date.
- **Which lab produced it.** The lab determines the method and the reference range.
- **Which page you are on.** Long reports repeat panels across pages, and a value can appear twice.

## Step 1: confirm the person and the dates

The collection date is when the sample was taken. The report date is when the result was released. They are often a day or two apart. A value from last Tuesday and a value from last year are not the same kind of information.

If the dates look wrong, or the report has two dates that are weeks apart, ask the lab before treating the result as current.

## Step 2: read the full test name

Abbreviations are where most of the confusion lives. SGOT is AST, SGPT is ALT, PCV is haematocrit, and TLC is the total white cell count. The report usually prints the full name beside the abbreviation, sometimes only once at the top of the panel.

Use the report's own expansion when it prints one. If it does not, our [blood test abbreviations guide](https://doctano.com/guides/blood-test-abbreviations) covers the common codes, including calculated indices that many lists skip.

## Step 3: keep the value attached to its unit

A glucose of 99 means nothing until you know whether the unit is mg/dL or mmol/L. The same number in the two units describes very different states. Read the unit column before you decide whether a value is high or low.

The same rule applies across reports. If one lab reports cholesterol in mg/dL and another in mmol/L, the numbers will look unrelated even when the result is similar.

## Step 4: use the range printed on that report

The reference range belongs to the lab, the method, and often the age and sex on the report. A chart from the internet cannot know any of that. The range on the page is the one that applies to the value on the page.

Some reports print a target rather than a population range, especially for LDL cholesterol. A target and a reference range are not the same thing. Our [reference ranges guide](https://doctano.com/guides/reference-ranges) explains the difference.

## Step 5: look at the flag and the remarks

H and L, or High and Low, are the lab's own comparison against its range. They are useful, but they are not a diagnosis, and a report can carry no flag simply because the lab does not flag that test.

Below the result, a remark can change how much weight to give it: sample hemolysed, fasting status not confirmed, test repeated, sample diluted. A value produced from a compromised sample is still a value, but it is a weaker one.

## Step 6: read the values as a panel, not a list

Some markers are only meaningful together: ALT with AST, urea with creatinine, TSH with free T4, LDL with triglycerides. A page of isolated numbers hides the pattern that a panel makes visible. For a panel-by-panel walkthrough, see [the panel pages](https://doctano.com/panels/); for one result in detail, see [the test pages](https://doctano.com/tests/).

## Step 7: compare with your own history

The most useful comparison is not against the population range. It is against your last result, from a comparable lab, under comparable conditions. One reading is a data point; three readings are a direction.

Doctano keeps each marker's values across reports and links every value back to the report it came from, so this step does not depend on a folder of PDFs or a spreadsheet you have to maintain.

## A worked example

Here is a fictional excerpt, laid out the way many labs print one.

| Test | Result | Unit | Reference | Flag |
| --- | --- | --- | --- | --- |
| Haemoglobin | 13.4 | g/dL | 13.0-17.0 | Normal |
| Fasting glucose | 104 | mg/dL | 70-99 | High |
| HbA1c | 5.9 | % | 4.0-5.6 | High |
| LDL cholesterol | 128 | mg/dL | Below 100 | High |
| TSH | 2.1 | uIU/mL | 0.4-4.0 | Normal |
| Vitamin D (25-OH) | 18 | ng/mL | 30-100 | Low |

Read in order, this is two results inside their ranges, four flags, and one pattern worth taking to a doctor: a fasting glucose and HbA1c just above the lab's limits, an LDL above the printed target, and a vitamin D below its range. None of that is a diagnosis. It is a list of questions for the next conversation, checked against your previous report.

## What the report cannot tell you

- Whether a value is a trend or a one-off. That needs earlier results.
- Why it changed. A number does not carry a cause.
- What to do about it. That depends on your history, symptoms, medicines, and examination.
- Whether the sample was representative. That is what the remarks are for.

Those questions need your history and a qualified professional. A report is evidence, not a plan.

## Reading a report

**How do I read a lab report without a medical background?**

Read it in a fixed order: the test name, the value, the unit, the range printed on that report, the flag, any remarks, then your previous result for the same marker. That order prevents the most common mistake, which is judging a number before knowing its unit and range.

**What do H and L mean on a lab report?**

H means the result is above the lab's reference range and L means it is below. They are the lab's own flags, not a diagnosis. A flag is a prompt to look at the range, the unit, and the history.

**Why is the range on my report different from one online?**

Reference ranges depend on the lab's method, equipment, and reference population, and sometimes on age and sex. A range from another source may describe a different measurement system. The range on your report is the one that applies to your value.

**What if my result is only slightly outside the range?**

A single value just outside a range is common, and it is weak evidence on its own. Check whether the value changed from your previous report, whether the sample was fasting, and whether the report carries a remark. If it persists or you have symptoms, ask a doctor.

**Should I compare results from different labs?**

Only with care. Two labs can use different methods and units, so a small difference may be the assay rather than you. A comparison from the same lab is cleaner. Doctano normalizes names and units, but it cannot remove the underlying difference between two methods.

## Links

- [Homepage](https://doctano.com/)
- [Lab report tracker](https://doctano.com/lab-report-tracker)
- [Blood test abbreviations](https://doctano.com/guides/blood-test-abbreviations)
- [Reference ranges](https://doctano.com/guides/reference-ranges)
- [Lab report units](https://doctano.com/guides/lab-report-units)
- [All guides](https://doctano.com/guides/)