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Table of Contents
Spirometry validation and reference values
Researchers from the University Medical Center Groningen performed a validation of the Pulmonary Function Test from participants at 1A visit 1 and 2A visit 1 (sections: physical state (Pulmonary Function Test) and secondary & linked variables).
The gender index can be requested in the Lifelines catalogue (coming soon) or by mail (data@lifelines.nl).
Validation
Spirometry is performed according to Standard Operating Procedures using the WEllch Allyn SpiroPerfect device. Judgment on technical correctness is performed by a Lifelines assistant, a pulmonologist, or both, according to a standard review procedure. Only data from pulmonary function tests that are judged to be technically correct should be used in the analyses. Technically correct is defined as:
- Test performed according to ATS criteria or
- Test not performed according to ATS criteria, but clinically reliable.
In case both the pulmonologist and the Lifelines assistant judged the technical correctness, the priority is given to the judgment of the pulmonologist.
Validation rules
To select only technically valid measurements the following rules were applied:
| IF… | THEN… |
| Review specialist is “ATS” (1) or “Not ATS, clincally reliable” (2) | Spirometry is technicall correct |
| Review specialist is “Not ATS, not to assess” (3) | Spirometry is not technically correct |
| Review specialist is missing or “No announcement” (0) and Review assistant is “ATS” (1) or “Not ATS, clincally reliable” (2) | Spirometry is technicall correct |
| Review specialist is missing or “No announcement” (0) and Review assistant is “Not ATS, not to assess” (3) | Spirometry is not technically correct |
| Other case | Spirometry is not technically correct |
Reference values
Reference values based on age, height, and sex are calculated based on the Global Lung Function Initiative (GLI) using the GLI provided syntax codes and databases.
Remarks UMCG researcher
- It is important to note that ethnicity has not been taken into account. Everyone has been treated as Caucasian.
- There are a few adults subjects with a huge difference in height between 1A visit 1 and 2A visit 1 resulting in a huge difference in reference values. It is recommended to exclude the adult subjects with a height difference of more than 5 cm using the height variable.
Variables
| Questions English | Questions Dutch | Code | Variable | Assessment | Age |
| Identifier for technically correct spirometry (baseline) | spiro_ok_baseline | 1A | 8+ | ||
| Predicted FEV1 value at baseline | FEV1_predicted_baseline | 1A | 8+ | ||
| Predicted FEV1FVC value at baseline | FEV1FVC_predicted_baseline | 1A | 8+ | ||
| Predicted FVC value at baseline | FVC_predicted_baseline | 1A | 8+ | ||
| Predicted FEF75 value at baseline | FEF75_predicted_baseline | 1A | 8+ | ||
| Predicted FEF25_75 at baseline | FEF2575_predicted_baseline | 1A | 8+ | ||
| Zscore FEV1 value at baseline | FEV1_zscore_baseline | 1A | 8+ | ||
| Zscore FEV1FVC value at baseline | FEV1FVC_zscore_baseline | 1A | 8+ | ||
| Zscore FVC value at baseline | FVC_zscore_baseline | 1A | 8+ | ||
| Zscore FEF75 value at baseline | FEF75_zscore_baseline | 1A | 8+ | ||
| Zscore FEF25_75 value at baseline | FEF2575_zscore_baseline | 1A | 8+ | ||
| Lower limit of normal FEV1 at baseline | FEV1_LLN_baseline | 1A | 8+ | ||
| Lower limit of normal FEV1FVC at baseline | FEV1FVC_LLN_baseline | 1A | 8+ | ||
| Upper limit of normal FEV1FVC at baseline | FEV1FVC_ULN_baseline | 1A | 8+ | ||
| Lower limit of normal FVC at baseline | FVC_LLN_baseline | 1A | 8+ | ||
| Lower limit of normal FEF75 at baseline | FEF75_LLN_baseline | 1A | 8+ | ||
| Lower limit of normal FEF25_75 at baseline | FEF2575_LLN_baseline | 1A | 8+ | ||
| FEV1 % predicted at baseline | fev1pp_baseline | 1A | 8+ | ||
| FVC % predicted at baseline | fvcpp_baseline | 1A | 8+ | ||
| FEV1FVC % predicted at baseline | fev1fvcpp_baseline | 1A | 8+ | ||
| FEF75 % predicted at baseline | fef75pp_baseline | 1A | 8+ | ||
| FEF2575 % predicted at baseline | fef2575pp_baseline | 1A | 8+ | ||
| Identifier for technically correct spirometry (second assessment) | spiro_ok_2ndass | 2A | 18+ | ||
| Predicted FEV1 value at 2ndass | FEV1_predicted_2ndass | 2A | 18+ | ||
| Predicted FEV1FVC value at 2ndass | FEV1FVC_predicted_2ndass | 2A | 18+ | ||
| Predicted FVC value at 2ndass | FVC_predicted_2ndass | 2A | 18+ | ||
| Predicted FEF75 value at 2ndass | FEF75_predicted_2ndass | 2A | 18+ | ||
| Predicted FEF25_75 at 2ndass | FEF2575_predicted_2ndass | 2A | 18+ | ||
| Zscore FEV1 value at 2ndass | FEV1_zscore_2ndass | 2A | 18+ | ||
| Zscore FEV1FVC value at 2ndass | FEV1FVC_zscore_2ndass | 2A | 18+ | ||
| Zscore FVC value at 2ndass | FVC_zscore_2ndass | 2A | 18+ | ||
| Zscore FEF75 value at 2ndass | FEF75_zscore_2ndass | 2A | 18+ | ||
| Zscore FEF25_75 value at 2ndass | FEF2575_zscore_2ndass | 2A | 18+ | ||
| Lower limit of normal FEV1 at 2ndass | FEV1_LLN_2ndass | 2A | 18+ | ||
| Lower limit of normal FEV1FVC at 2ndass | FEV1FVC_LLN_2ndass | 2A | 18+ | ||
| Upper limit of normal FEV1FVC at 2ndass | FEV1FVC_ULN_2ndass | 2A | 18+ | ||
| Lower limit of normal FVC at 2ndass | FVC_LLN_2ndass | 2A | 18+ | ||
| Lower limit of normal FEF75 at 2ndass | FEF75_LLN_2ndass | 2A | 18+ | ||
| Lower limit of normal FEF25_75 at 2ndass | FEF2575_LLN_2ndass | 2A | 18+ | ||
| FEV1 % predicted at 2ndass | fev1pp_2ndass | 2A | 18+ | ||
| FVC % predicted at 2ndass | fvcpp_2ndass | 2A | 18+ | ||
| FEV1FVC % predicted at 2ndass | fev1fvcpp_2ndass | 2A | 18+ | ||
| FEF75 % predicted at 2ndass | fef75pp_2ndass | 2A | 18+ | ||
| FEF2575 % predicted at 2ndass | fef2575pp_2ndass | 2A | 18+ | ||
| Change in FEV1 (L/year) between baseline and 2ndass | dfev1 | ||||
| Change in FVC (L/year) between baseline and 2ndass | dfvc | ||||
| Cchange in FEV1FVC (per year) between baseline and 2ndass | dfev1fvc | ||||
| Change in FEF75 ((L/sec)/year) between baseline and 2ndass | dfef75 | ||||
| Change in FEF2575 ((L/sec)/year) between baseline and 2ndass | dfef2575 | ||||
| Difference in height between baseline and 2ndass | heightdifference_adults |
