Blood Test Results Glossary: Common Report Terms Explained
Blood test reports contain more than numbers. You may also see comments such as high, low, borderline, haemolysed, fasting, positive, inconclusive or repeat sample required.
These terms describe how the result compares with a laboratory interval, whether the target of a test was detected, whether the specimen was suitable, whether preparation instructions were followed, and whether the result was changed, confirmed or repeated. They do not automatically provide a diagnosis.
A–Z glossary of common report terms
Abnormal
A result described as abnormal does not fit the expected pattern or is outside the laboratory’s reference interval. “Abnormal” does not automatically mean dangerous or diagnostic. The amount of change, the test, symptoms, previous results and clinical context all matter.
Above range / High / H
The result is above the upper limit shown by that laboratory. A high flag is a comparison with the reporting interval. It does not show why the result is high or whether treatment is required.
Add-on test
An add-on is an extra test requested on a sample that has already been collected. Whether it can be performed depends on the correct specimen type being available, enough sample remaining, sample stability, time since collection, and laboratory policy.
Amended result / Corrected result
An amended or corrected result replaces or updates a previously issued report. This may happen after a transcription correction, additional review, confirmatory testing, identification of an analytical issue, a revised organism identification, or updated clinical information. The corrected report should state what changed.
Below range / Low / L
The result is below the lower limit shown by that laboratory. As with a high result, the flag alone does not diagnose a condition.
Borderline
A borderline result is close to a threshold, reference limit or decision point. Depending on the test, a clinician may review symptoms and risk factors, compare previous results, repeat the test, order a different test, or monitor the trend. “Borderline” is not a universal laboratory category. Its meaning depends on the test and local clinical guidance.
Clotted sample
A clotted sample contains a clot when the requested test required anticoagulated blood. This is especially relevant to full blood count samples, some coagulation samples, and selected specialist tests. Clotting can make cell counts or clotting tests unreliable, so another sample may be needed.
Comment added / See comment
The laboratory has added text that may explain a limitation, specimen problem, calculation, recommended repeat, test-selection issue, interpretive note, or a result that cannot be reported numerically. Always read the complete comment.
Confirmed
A confirmed result has been supported by repeat analysis or another method, according to the test pathway. The type of confirmation varies and may involve repeating the same test, testing a second sample, using a more specific method, culture identification, microscopic review, or specialist laboratory testing.
Contaminated sample
A contaminated sample contains material that may not represent the intended body site. Examples include skin organisms entering a blood culture bottle, stool contaminating a urine specimen, or vaginal contamination of a urine sample. Contamination can make interpretation difficult and may require recollection.
Critical result / Critical value
A critical result is a result that may represent an immediate risk and requires urgent communication under the laboratory’s policy. Critical limits are not the same as reference intervals. They are action thresholds designed for rapid notification.
Detected / Not detected
These terms are common in molecular and microbiology reports. Detected means the target was found. Not detected means the target was not found above the test’s detection limit. “Not detected” does not always exclude infection. Timing, sample quality and test sensitivity matter.
Equivocal
An equivocal result is not clearly positive or negative. It may occur because the result is near a cut-off or the test response is uncertain. Repeat or confirmatory testing may be recommended.
Estimated
An estimated result is calculated rather than measured directly. Examples include eGFR, calculated LDL cholesterol in some reports, adjusted calcium, and certain risk scores. Calculated results depend on the accuracy and assumptions of the inputs.
Fasting
A fasting sample was collected after the person followed instructions not to eat or drink anything except plain water for a specified period. The required duration depends on the test and local instructions. Do not fast unless the healthcare provider or laboratory asks you to.
Final result
A final result is the completed report issued after the laboratory has finished the relevant testing and review. A final microbiology report may replace earlier preliminary updates.
Haemolysed / Hemolysed sample
A haemolysed sample contains red blood cells that have broken open, releasing their contents into the serum or plasma. Haemolysis can occur during a difficult blood draw, through collection or handling problems, during transport, or less commonly because red cells were breaking down within the body before collection. Sample haemolysis can interfere with tests, particularly potassium and some enzymes. The laboratory may withhold affected results and request another sample. A haemolysed sample comment usually describes the specimen, not automatically a disease in the patient.
Haemolysis index
Some analysers estimate the amount of haemolysis in a sample. The laboratory may use this index to decide whether a result can be released, released with a comment, or rejected.
Icteric sample
An icteric sample contains a high amount of bilirubin and may appear deeply yellow. Icterus may reflect a genuine bilirubin increase and can also interfere with some analytical methods.
Inconclusive / Indeterminate / Uncertain
The test did not produce a clear positive or negative answer. Possible next steps include repeating the test, collecting a new sample, using a confirmatory method, waiting for a more appropriate testing interval, or interpreting with other findings.
Insufficient sample / QNS
QNS means quantity not sufficient. There was not enough specimen to perform or complete the requested test. This can happen when the tube is underfilled, several tests compete for a small sample, a sample leaks, or the analyser requires a minimum volume.
Interference
An interference is a substance or specimen property that affects the accuracy of the analytical method. Examples include haemolysis, lipaemia, icterus, certain medicines, biotin, antibodies that react with an assay, and very high or low protein concentrations. The laboratory may add a comment or use another method.
Lipaemic / Lipemic sample
A lipaemic sample contains enough lipid particles to appear cloudy. It may occur after eating, with very high triglycerides or in other metabolic situations. Lipaemia can interfere with some measurements.
Negative / Non-reactive
A negative or non-reactive result generally means the test did not detect the target. This does not always rule out a condition. The sample may have been taken too early, the target may be below the detection limit, or the condition may require another type of test.
Non-fasting
A non-fasting sample was collected without a period of fasting. Many modern tests can be interpreted without fasting. Whether fasting matters depends on the test and clinical question.
Pending
A pending result is not ready yet. Reasons include culture time, confirmatory testing, referral to another laboratory, specialist review, batch testing, or technical delay.
Positive / Reactive
A positive or reactive result means the test detected the target or produced a response above its cut-off. The target may be an organism, antigen, antibody, gene or variant, drug, or hormone. A positive screening test may still require confirmation.
Preliminary result
A preliminary result is an early report issued before the testing process is complete. This is common in microbiology. For example, a blood culture may be preliminarily reported as positive before the organism is fully identified and susceptibility results are available.
Quantitative result
A quantitative result gives a number, such as glucose concentration, haemoglobin, CRP, viral load, or hormone level.
Qualitative result
A qualitative result uses categories such as positive/negative, detected/not detected, reactive/non-reactive, or present/absent.
Reference interval
The range printed beside a numerical result and derived from an appropriate reference population or verified by the laboratory. Being outside the interval does not automatically mean disease. Being within it does not guarantee health.
Rejected sample
A rejected sample was not accepted for testing. Common reasons include missing or incorrect identification, wrong tube, insufficient volume, clotted specimen, leakage, excessive delay, unsuitable transport temperature, contamination, or incorrect collection time.
Repeat sample / Recollection required
The laboratory or clinician needs another specimen. This may be because the original sample was unsuitable, the result needs confirmation, the result was unexpected, the test requires a second specimen, or the condition is being monitored over time. A repeat request does not necessarily mean something serious was found.
Sample unsuitable
The sample cannot produce a reliable result for the requested test. The report should ideally explain the reason, such as haemolysis, clotting, wrong tube or insufficient volume.
Therapeutic range
A therapeutic range is a target drug concentration associated with effectiveness and acceptable toxicity. It is not the same as a reference interval based on healthy people.
Trend
A trend is the direction of results over time. A series of results may be more informative than one measurement because it shows whether the value is stable, rising, falling, fluctuating, or returning towards baseline.
Unverified / Not authorised
The result has not completed the laboratory’s full review or authorisation process. Patients should not act on an unverified result without professional guidance.
Result term versus diagnosis
| Report wording | What it tells you | What it does not tell you |
|---|---|---|
| High / low | Position relative to a limit | The cause |
| Positive / negative | Whether the test detected its target | The entire clinical diagnosis |
| Haemolysed | A specimen-quality issue may be present | That you have haemolytic disease |
| Borderline | Close to a threshold | That disease is confirmed |
| Critical | Urgent communication threshold | The final diagnosis |
| Repeat sample | Another specimen is needed | That the first result was dangerous |
What to do when a report term is unclear
- Read the complete report and comments.
- Check whether the result is final or preliminary.
- Compare with the interval on that report.
- Check whether fasting or another preparation instruction applied.
- Review the result with the healthcare professional who ordered it.
- Seek urgent medical care for severe symptoms rather than waiting for online interpretation.
Summary
Laboratory report terms describe the numerical result, specimen quality, test status or need for follow-up. They should be interpreted with the exact test, the reference interval or decision limit, symptoms, previous results, medicines and health conditions, and the reason the test was ordered.
FAQ
What does a haemolysed blood sample mean?
Red blood cells broke open in the sample. This may interfere with certain results and can lead to a repeat request.
Does “positive” always mean I have a disease?
No. It means the test detected its target or reacted above a cut-off. Screening results may need confirmation, and the clinical meaning depends on the test.
What does “borderline” mean?
The result is close to a reference limit or decision threshold. It may be repeated or interpreted with other information.
Why has the laboratory asked for another sample?
Common reasons include insufficient volume, haemolysis, clotting, incorrect labelling, contamination or a need to confirm the result.
Is an abnormal result always serious?
No. “Abnormal” may simply mean outside the laboratory’s interval. The clinical significance depends on the test and context.
This glossary explains general laboratory wording. It cannot determine what an individual result means for your health.
Read next: What Is a Reference Interval?