# How to spot a wrong blood test result

> 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 wrong results are not bad chemistry. They are a tube, a label, a delay, or a typo.

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A wrong result usually comes from something around the measurement: a mislabelled tube, the wrong tube type, a delayed sample, a transcription or unit error, or a mixed-up report. The number itself is rarely wrong in isolation. Check the original, then ask the lab for a repeat on a fresh sample.

Many laboratory errors happen before the sample reaches the analyser, or after the result leaves it. That is useful to know, because it tells you what to check first.

## Where errors happen

- **Before analysis:** patient identification, tube type, collection technique, timing, transport, and storage.
- **During analysis:** an instrument or reagent problem, interference from the sample, or a result outside the measuring range.
- **After analysis:** transcription, unit conversion, reporting to the wrong patient, or a report released with the wrong range.

## Common causes

- **A mislabelled tube.** The result may belong to another patient.
- **The wrong tube type.** EDTA tubes can raise potassium and lower calcium if their contents contaminate the sample. Citrate tubes dilute the blood.
- **Haemolysis.** A difficult draw can break red cells and raise potassium, LDH, and AST.
- **Delayed processing.** Glucose can fall and potassium can rise while cells sit in the tube.
- **Fasting not observed.** Glucose and triglycerides can be different from a fasting sample.
- **Dilution from an IV line.** Blood drawn near a running line can be diluted.
- **Platelet clumping.** Platelets can clump in an EDTA tube and produce a falsely low count.
- **Transcription or unit errors.** A digit or a decimal point can move.
- **Mixed-up reports.** A portal can show one person report under another name.

## How to spot one

A wrong result often looks wrong in context. It is far outside the range with no explanation, it jumps from normal to extreme between two samples, it disagrees with a test that should move with it, or its unit does not match its range.

| What you notice | Possible cause | What to ask for |
| --- | --- | --- |
| Potassium much higher than usual, no symptoms | Haemolysis or EDTA contamination | A repeat on a fresh sample, with the tube type checked |
| Platelets low with no bruising or bleeding | Clumping in the tube | A repeat, sometimes in a different tube |
| Glucose lower than expected after a delay | Cells used glucose before processing | A repeat with prompt processing |
| One result does not fit the rest of the panel | Transcription or unit error | The original report and a lab verification |
| Name, age, or date does not match | Wrong patient or mixed report | The laboratory records team |
| Haemoglobin and haematocrit disagree | A diluted or haemolysed sample, or a calculation error | A repeat |

## What to check first

1. Open the original report and check the patient details.
2. Check the collection date and time.
3. Check the unit and the reference range.
4. Read every remark on the report.
5. Compare with the previous result for the same test.
6. Look for a duplicate report before assuming a change.

## How to ask for a repeat

Contact the doctor who ordered the test, or the laboratory patient services desk. Give the report or accession number, the date, and the test. Ask whether the sample can be checked and whether a repeat on a fresh sample is appropriate. Keep both reports, so the change is documented.

## When a repeat may not help

A value that is consistent with your history, a known biological variation, or a remark that explains the result may not need a repeat. That is a conversation with the clinician, not a conclusion from a list of causes.

## What Doctano can and cannot do

Doctano keeps every value linked to the original report, so you can compare the extracted value with the document. Extraction can itself be wrong or incomplete. Doctano does not detect a laboratory error, and it cannot tell you whether a sample was valid.

## Wrong results, answered

**How do I know if my blood test result is wrong?**

You usually cannot tell from one number. Look for a value that is implausible for you, a sudden jump, a mismatch with a related test, a unit that does not fit the range, or a patient-detail mismatch, then ask the lab to verify.

**Can a lab mix up samples?**

Misidentification is a known laboratory error. It is not common, and labs have checks for it, but it happens. The first thing to check is that the name, age, and date on the report are yours.

**What causes a falsely high potassium?**

Haemolysis, contamination from an EDTA tube, a delay before the serum is separated, and a difficult draw can all raise the measured potassium. A repeat on a fresh sample is the usual check.

**Should I repeat the test at the same lab?**

Usually, because a repeat at the same lab removes method differences and makes the comparison cleaner. Follow your doctor's advice about where and when to repeat.

**What if the lab will not repeat it?**

Ask the doctor who ordered the test to request a verification or a repeat. Keep the original report, note what you were told, and seek a second opinion if the result matters to your care.

## Limits

**An error is not a diagnosis either.** A strange value may be a lab problem, a real change, or something in between. Ask for verification, and do not change treatment on your own.

## Links

- [Homepage](https://doctano.com/)
- [Lab report tracker](https://doctano.com/lab-report-tracker)
- [Lab report remarks](https://doctano.com/guides/lab-report-remarks)
- [Same test, different lab](https://doctano.com/guides/same-test-different-lab)
- [How to read a lab report](https://doctano.com/guides/how-to-read-a-lab-report)
- [Track results over time](https://doctano.com/guides/track-lab-results-over-time)
- [All guides](https://doctano.com/guides/)