Assigns one of grades A-F to a set of acceptable spirometry maneuvers for a single measure (FEV1 or FVC) per the Graham et al. ATS/ERS 2019 technical standard, Table 10. Grades depend on the number of acceptable maneuvers and the difference between the best two values.
Arguments
- values
Numeric vector of measurements (litres) from each acceptable maneuver for ONE patient and ONE measure. Length 0 is allowed and yields grade
"F".- age
Patient age, in years. The repeatability thresholds tighten for children aged 6 or younger; the threshold is the greater of the absolute child value (0.100 / 0.150 / 0.200 L for A / C / D) and 10% of the highest measured value, per Table 10's footnote. Defaults to
NA_real_, which uses the adult thresholds.
Details
Grade definitions (Table 10, paper p. e83). Adult thresholds in
parentheses; child (age <= 6) thresholds are max(absolute, 0.10 · max(values)):
A: >= 3 acceptable maneuvers; best two within 0.150 L (0.100 L for child).
B: 2 acceptable maneuvers; best two within 0.150 L (0.100 L for child).
C: >= 2 acceptable maneuvers; best two within 0.200 L (0.150 L for child).
D: >= 2 acceptable maneuvers; best two within 0.250 L (0.200 L for child).
E: >= 2 acceptable maneuvers with best-two diff exceeding the D threshold, OR exactly 1 acceptable maneuver.
F: 0 acceptable maneuvers.
Grade U ("0 acceptable AND >= 1 usable") from Table 10 is NOT currently distinguished from F. Implementing U would require extending the API to take a separate vector of usable-but-not- acceptable maneuvers; with zero acceptable values, the function returns F unconditionally.
References
Graham BL, Steenbruggen I, Miller MR, et al. Standardization of Spirometry 2019 Update. An Official American Thoracic Society and European Respiratory Society Technical Statement. Am J Respir Crit Care Med. 2019;200(8):e70-e88. doi:10.1164/rccm.201908-1590ST .
See also
pft_interpret() for the downstream interpretation once
acceptable maneuvers have been selected.
Examples
pft_quality(c(3.20, 3.12, 3.10)) # Grade A (n>=3 within 0.150)
#> [1] "A"
pft_quality(c(3.20, 3.12)) # Grade B (n=2 within 0.150)
#> [1] "B"
pft_quality(c(3.20, 3.02)) # Grade C (n>=2 within 0.200)
#> [1] "C"
pft_quality(c(3.20, 2.97)) # Grade D (n>=2 within 0.250)
#> [1] "D"
pft_quality(c(3.20, 2.80)) # Grade E (n>=2 diff > 0.250)
#> [1] "E"
pft_quality(c(3.20)) # Grade E (only 1)
#> [1] "E"
pft_quality(numeric(0)) # Grade F (none)
#> [1] "F"