To compare two reports, match the same test by name and by what it measures, convert both values to one unit, and use the reference range printed on each report. Check whether the lab, fasting, and timing match. Then read the pair as one step in a trend, not as a verdict.
Most false alarms in a comparison come from matching the wrong things: two names for one test, two units for one value, or two ranges for one number.
Step 1: match the test
Make sure both reports describe the same measurement. SGOT and AST are the same enzyme, SGPT and ALT are the same enzyme, and PCV and haematocrit are the same measure. A test with a similar name can still be different: total T3 and free T3 are not interchangeable, and total testosterone and free testosterone are not the same result.
Step 2: match the unit
Convert both values to the same unit before comparing. A cholesterol value of 200 mg/dL is about 5.2 mmol/L. A creatinine of 1.0 mg/dL is about 88 umol/L. The unit conversion guide lists the common factors.
Step 3: use each report's own range
Each lab prints its own reference range, and some ranges are targets rather than population intervals. A value can be inside one report's range and outside the other while the measurement has not changed. Compare the flag in the context of that report.
Step 4: check the lab and method
If the two reports come from different labs, part of any difference may be the assay. Note the lab beside each value. A same-lab series is cleaner, and a change that coincides with a lab switch deserves more caution.
Step 5: check the conditions
Fasting status, time of day, recent illness, a new medicine, exercise, alcohol, pregnancy, and the menstrual cycle can move a result. Write down anything that changed between the two samples, especially if the difference is unexpected.
Step 6: read the gap
A change over three years and the same change over three weeks are different signals. Direction matters too: two points show a difference, but three or more show a direction. Do not read a pair as a trend unless the two results are comparable.
| What to line up | Why it matters | Example |
|---|---|---|
| Test name | Synonyms can hide a match | SGOT is AST |
| Unit | The same number can mean different things | mg/dL and mmol/L |
| Reference range | The flag can flip while the value does not | Lab A and lab B |
| Lab and method | A small offset can come from the assay | Two labs, one marker |
| Collection date | The gap changes what a difference means | Three weeks or three years |
| Conditions | Fasting, illness, and timing move some values | Fasting and non-fasting glucose |
Compare panels, not just single values
- Liver: ALT, AST, ALP, and GGT move together in different patterns.
- Kidney: creatinine is read with eGFR and urine albumin, and urea adds context.
- Blood count: haemoglobin, haematocrit, MCV, and ferritin tell a fuller story than haemoglobin alone.
- Thyroid: TSH is read with free T4, and sometimes with TPO antibodies.
- Lipids: total cholesterol, LDL, HDL, and triglycerides belong together.
- Iron: iron, ferritin, and TIBC are more useful as a group than alone.
What a difference does not prove
A comparison shows that two numbers differ. It does not show why, whether the difference matters, or what to do. That judgment needs the whole report, your history, and a clinician.
How Doctano compares reports
Doctano normalizes marker names and units across reports, keeps the reference range from each report, and places every result on one timeline linked to its source. It does not decide what a difference means. Verify important values against the original reports.