At a glance
- Read the measurement name, units and column heading together.
- Reference comparisons and test comments need clinical context.
- Use the report to ask questions, not to diagnose yourself or change treatment.
01
Start with the question the test was meant to answer
A spirometry report records how much air you breathed out and how quickly you did it. A clinician may use it to investigate breathing symptoms or follow a known condition. Reading the labels can help you take part in that conversation, but a number on its own does not explain the cause of a symptom. Your history, symptoms and other findings still matter.
Check that the report belongs to you and note its date. Keep the complete report, including comments and any interpretation, rather than a screenshot of one highlighted result. Ask who will explain it and whether this was spirometry alone or part of a wider set of lung function tests. Different tests measure different aspects of breathing.
Read about COPD and its diagnosis
02
Separate the measurement from the comparison
Read the row name and column heading together. The same measurement may appear as an amount, a reference value and a percentage. Those entries answer different questions. The table below is a guide to labels, not a sample patient report or a set of targets to reach.
| Label | What it describes | What to clarify |
|---|---|---|
| FEV1 | The amount breathed out in the first second of a forceful exhalation after a full breath in. | Is this the measured amount or its comparison with a reference? |
| FVC | The total amount breathed out during that forceful exhalation. | Which column contains the measured amount? |
| FEV1/FVC | The ratio of the first-second amount to the total amount. | How does this ratio fit with the other findings? |
| Measured or actual | The result recorded during your test. | What are the units, and was this before or after medicine? |
| Predicted or reference | A comparison value calculated using a reference equation. | Which reference is being used for this report? |
| % predicted | The measured result expressed as a percentage of its predicted value. | Which measurement does this percentage describe? |
FEV1/FVC and FEV1 expressed as a percentage of predicted are different comparisons. Avoid describing either simply as “my lung percentage.” Write down the full label when asking a question. A report may also show a reference range or a z-score; ask the clinician to explain the comparison used rather than applying a threshold from another report.
03
Check before-and-after columns and previous reports
Some tests include measurements before and after an inhaled medicine that opens the airways, called a bronchodilator. Labels such as “pre” and “post” can refer to those stages. Ask which medicine was used and what the comparison contributes to the clinical assessment. The columns are not instructions to take extra medicine or change your usual treatment.
When bringing an older report, keep its date, full labels and comments visible. Ask whether the reports used comparable testing conditions and reference equations. A change in a reference comparison is not automatically the same as a change in the measured amount. Your clinician can explain which comparisons are useful for the question being investigated.
04
Read the comments as well as the numbers
Spirometry needs active participation, coaching and repeated attempts to obtain useful measurements. A poor seal around the mouthpiece can affect accuracy. If the report mentions difficulty with the test or uncertainty about the results, ask how that limits the interpretation and whether any further testing is needed. You do not need to assign a technical quality grade yourself.
Tell the clinician what happened during the appointment if it is missing from the report: what you found difficult, whether you could follow the instructions, and which medicines you had taken. Keep a distinction between your recollection and the laboratory's comments. Ask the team to resolve anything unclear instead of deciding that a difficult test must be either useless or reassuring.
05
Leave with an explanation and a follow-up plan
Bring the report, an up-to-date medicine list and a brief description of your breathing concerns. Choose the questions that remain unanswered rather than trying to interpret every field. Before leaving, write down who will arrange any next step and how you will receive the explanation or results.
- What clinical question does this result help answer, and what remains uncertain?
- Which measured values and reference comparisons matter in my case?
- Do the test comments limit what you can conclude?
- What do the before-and-after results add to the assessment?
- Do I need another test or appointment, and who will arrange it?
Prepare an accurate medicine list
Sources
- Lung Function TestsMedlinePlus, National Library of Medicine · 2023Source accessed:
- Pulmonary function testsA.D.A.M. Medical Encyclopedia, MedlinePlus · 2025Source accessed:
- The Importance of Pulmonary Function TestsAmerican Lung Association · 2026Source accessed:
- Pulmonary Function TestsAmerican Lung AssociationSource accessed:
- COPD DiagnosisNational Heart, Lung, and Blood Institute · 2024Source accessed:
- Respiratory physiology at UCLHUniversity College London Hospitals NHS Foundation TrustSource accessed:
- Spirometry testNHS · 2025Source accessed:
Revision history
- Initial English, Spanish and Japanese article prepared with automated assistance. The cited patient resources were checked for the complete article on 2026-10-15T02:24:13Z (UTC). Publication and preparation use the current date; no historical date was assigned. No independent clinical review is recorded.