Protocol - Lung Function - Diffusion Capacity

Add to My Toolkit

The American Thoracic Society (ATS) and the European Respiratory Society (ERS) Task Force recommendations for standardisation of the single-breath determination of carbon monoxide uptake in the lung outlines principles for performing high-quality single-breath carbon monoxide diffusing capacity (DLCO) testing. Topics covered include necessary equipment (e.g., gas analyzers), standardization issues associated with single-breath testing technique, and how to evaluate the quality of measurements of DLCO, calculations, definitions and abbreviations.

These recommendations for the single-breath determination of carbon monoxide uptake in the lung are part of a series of recommendations by the ATS/ERS Task Force for the standardization of lung function testing, which can be found on the ATS website at www.thoracic.org/statements/pulmonary-function.php. Detailed information regarding patient preparation is included in the general considerations section of the recommendations for lung function testing in this series.

Specific Instructions:

A comprehensive evaluation of lung function requires investigation of various aspects of the lung, such as diffusion capacity and lung volume. Hence, the American Thoracic Society (ATS) and the European Respiratory Society (ERS) Task Force have published a series of documents regarding pulmonary function testing. The Sickle Cell Disease: Cardiovascular, Pulmonary, and Renal Working Group recommends researchers access the ATS website (www.thoracic.org/) to view other documents in this series that may apply to their area of research.

Also please note, per www.thoracic.org/statements/resources/pft/pft4.pdf: If clinically acceptable, the subject should not breathe supplemental oxygen for 10 minutes prior to a standard test.

At least 4 minutes should be allowed between tests to allow an adequate elimination of test gas from the lungs. The subject should remain seated during this interval. In patients with obstructive airway disease, a longer period (e.g., 10 minutes) should be considered.

The average of at least two acceptable tests should be reported (i.e., outliers excluded).The report should always include the unadjusted measured carbon monoxide diffusing capacity (DLCO), the predicted DLCO for the subject, and percent predicted DLCO achieved. Additionally, the alveolar volume (VA) should be obtained and the DLCO/VA (predicted and percent predicted) should be reported. Any adjustments (e.g., for Hb, COHb, PI, or O2,) should also be reported along with the data used to make the adjustment.


Lung Function Testing: Single-breath carbon monoxide diffusing capacity (DLCO)

The American Thoracic Society (ATS) and the European Respiratory Society (ERS) Task Force recommendations for standardisation of the single-breath determination of carbon monoxide uptake in the lung can be found here as well as on the ATS website: www.thoracic.org/statements/resources/pft/pft4.pdf

Protocol Name from Source:


Publicly available

Personnel and Training Required

Certified respiratory therapist who is also certified in the proper use of equipment for single-breath carbon monoxide diffusing capacity (DLCO).

Equipment Needs

A source of test gas (such as bag-in-box, spirometer, compressed gas cylinder)

A method for measuring inspired and expired volume over time (such as spirometers with kymographs, pneumotachometers near the mouthpiece or near a bag-in-box)

Gas analysers (single-sample analysers or continuous high-speed analysers)

Requirement CategoryRequired
Major equipment Yes
Specialized training Yes
Specialized requirements for biospecimen collection No
Average time of greater than 15 minutes in an unaffected individual No
Mode of Administration

Clinical assessment

Life Stage:

Child, Adolescent, Adult, Senior, Pregnancy


Individuals age 8 years old and older.

Selection Rationale

Although there are various methods to measure carbon monoxide diffusing capacity (DLCO) of the lung (such as steady-state, intra-breath, and rebreathing techniques), the single-breath technique is most commonly used worldwide.



Common Data Elements (CDE) Lung Function Outcome Score 2806422 CDE Browser
Derived Variables


Process and Review

This section will be completed when reviewed by an Expert Review Panel.


MacIntyre, N., Crapo, R. O., Viegi, G., Johnson, D.C., van der Grinten, C.P.M., Brusasco, V., Burgos, F., Casaburi, R., Coates, A., Enright, P., Gustafsson, P., Hankinson, J., Jensen, R., McKay, R., Miller, M.R., Navajas, D., Pedersen, O.F., Pellegrino, R. & Wanger, J. (2005). Standardisation of the single-breath determination of carbon monoxide uptake in the lung. European Respiratory Journal, 26, 720-735. doi:10.1183/09031936.05.00034905

General References

Arteta, M., Campbell, A., Nouraie, M., Rana, S., Onyekwere, O. C., Ensing, G., Sable, C., Dham, N., Darbari, D., Luchtman-Jones, L., Kato, G. J., Gladwin, M. T., Castro, O. L., Minniti, C. P., & Gordeuk, V. R. (2014). Abnormal pulmonary function and associated risk factors in children and adolescents with sickle cell anemia. Journal of Pediatric Hematology/Oncology, 36(3), 185-189.

Lunt, A., Desai, S. R., Wells, A. U., Hansell, D. M., Mushemi, S., Melikian, N., Shah, A. M., Thein, S. L., & Greenough, A. (2014). Pulmonary function, CT and echocardiographic abnormalities in sickle cell disease, Thorax 69(8), 746-751.

Protocol ID:


Export Variables
Variable NameVariable IDVariable DescriptionVersiondbGaP Mapping
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Concentration_TestGas PX810301060000 What is the gas concentration of the test gas? N/A
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_DeadSpace_Adult PX810301170000 For adults, is the dead space volume more
consisting of the volume from the valve, filter, and mouthpiece under 0.35 Liters? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_DeadSpace_AlveolarSample PX810301160100 What is the dead space volume measurement more
for the alveolar sample? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_DeadSpace_Volume PX810301150100 What is the dead space volume measurement more
for the inspired test gas? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_DeadSpace_VolumeMetric PX810301150200 How is this metric used in the more
data-computation above? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_DeadSpace_VolumeMetric2 PX810301160200 How is this metric used in the more
data-computation above? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Device_CoolGas PX810301380000 Does the device allow exhaled gases to cool more
(e.g. volume to contract)? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Device_RemoveCo2 PX810301360000 Does the device remove CO2 from the exhaled gas? N/A
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Device_RemoveH2o PX810301370000 Does the device remove H20 from the exhaled gas? N/A
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Equipment_CalibratedAccuracy PX810301040100 Is the device calibrated to accurately more
detect the exhaled carbon monoxide and the tracer gas concentrations, which is calculated between the inhaled (test gas concentrations) and zero measurement (no CO or tracer gas present in the device)? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Equipment_CalibratedDeviations PX810301040200 If so, are the deviations from the true more
measurement within 0.5% of the full scale? (for example, if 0.3% CO is used for the test gas, then the maximum error on any dilution should be no more than +/- 0.0015%) show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Equipment_CalibratedVolume PX810301030000 Regardless of the method being used, does more
the device maintain the required volume accuracy, regardless of the gas mixture, direction of gas flow (e.g. inhaled or exhaled), or pulsatile flow pattern? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Equipment_Method PX810301020100 Which of the following best describes the more
method for measuring inspired and expired volumes over time? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Equipment_Method_Other PX810301020200 Which of the following best describes the more
method for measuring inspired and expired volumes over time? Other show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Equipment_Regulator PX810301110100 Is a demand-flow regulator being used on a more
compressed test gas cylinder? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Equipment_Resistance PX810301110200 If no, is the circuit resistance of the more
device <1.5 cm*H20/L/s at 6 L/s flow? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Equipment_Resistance2 PX810301110300 If yes, is the circuit resistance of the more
device <10cm H20 at 6L/s inspiratory flow? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Equipment_Timing PX810301120000 Is the timing device accurate to within 1% more
(100ms over 10s)? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Equipment_TimingTechnique PX810301130000 What timing technique was used for more
calibration and/or testing? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_InspiredCO PX810301310000 Is the inspired CO around 0.3% of the more
collected volume? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_MeasuredConcentration_TestGas PX810301070000 What is the measured gas concentration of more
the test gas? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Observed_Drift PX810301080000 Is significant drift observed over the time more
scale of the test (~30 sec)? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Quality_Accuracy PX810301210100 Within the last 3 months, was the accuracy more
of the measured gas readings assessed? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Quality_AccuracyDate PX810301210200 If no, what is today's date (test date)? Variable Mapping
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Quality_Calibration PX810301200000 Was the calibration test performed with a more
'standard subject' (biological control) or simulator? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Quality_Leaks PX810301180000 Within the last week, was the device tested more
to be leak-free? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Quality_VolumeCalibration PX810301190000 Was the volume calibration test with the 3L more
syringe performed? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_ReadingStability_CO PX810301090000 Is the reading stable +/- 0.001% absolute for CO? N/A
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_ReadingStability_Tracer PX810301100000 Is the reading stable +/- 0.5% of the full more
scale reading for the tracer gas? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Results_Carboxyhemoglobin PX810301430000 Are carboxyhemoglobin levels < 2%? If not, more
needs to be considered in interpretation show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Standardization PX810301230000 Did the subject breathe supplemental oxygen more
for 10 min prior to this test? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Standardization_Broncodilator PX810301330000 Was a bronchodilator used? N/A
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Standardization_Exercise PX810301240100 Was the subject involved in any exercise more
prior to this test? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Standardization_ExerciseIntensity PX810301240200 If so, please describe the intensity level more
of the exercise. show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Standardization_LastCigarette PX810301270000 What time did the subject smoke his/her last more
cigarette? show less
Variable Mapping
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Standardization_SampleGasVolume PX810301290000 Is the sample gas volume collected between more
0.5-1.0L? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Standardization_SubjectDemonstration PX810301260000 Has a demonstration of the manuevers more
involved in the test and instructions been provided to the subject? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Standardization_Supine PX810301250100 Was the subject in a supine position prior more
to this test? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Standardization_SupineDuration PX810301250200 If so, please provide the duration of the more
patient in the supine position? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Standardization_TotalExhalation PX810301280100 What length of time did the subject need for more
total exhalation? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Standardization_TotalExhalationPlus PX810301280200 If total exhalation time > 4sec, please note more
the expiratory time in seconds show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Standardization_TracerType PX810301300100 What type of tracer gas was used? N/A
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Standardization_TracerTypeOther PX810301300200 What type of tracer gas was used? Other N/A
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Subject_Age PX810301390000 What is the age of the subject? Variable Mapping
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Subject_Height PX810301410000 What is the height of the subject? Variable Mapping
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Subject_Oad PX810301320100 Does the subject have obstructive airway disease? N/A
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Subject_OadRest PX810301320200 If so, were at least 10 minutes allowed more
between tests? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Subject_Race PX810301420000 What racial/ethnic group does the subject more
identify with? show less
Variable Mapping
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Subject_Rest PX810301340000 Were at least 4 minutes allowed between tests? N/A
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Subject_Seated PX810301350000 Did the subject remain seated during that more
interval? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Subject_Sex PX810301400000 What is the sex of the subject? Variable Mapping
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_TestGas PX810301010100 Which of the following best describes the more
source of test gas? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_TestGasOther PX810301010200 Which of the following best describes the more
source of test gas? Other show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Testing_NewTest PX810301220000 Was the device tared to zero after the last test? N/A
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Timing_AutomatedComputation PX810301140100 Does the timing equipment rely on automated more
data computation? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Timing_AutomatedComputationAccuracy PX810301140200 If so, how accurate is the breath-hold time more
computation? show less
PX810301_SingleBreath_CarbonMonoxide_DiffusingCapacity_Zero_Measurement PX810301050000 What is the measured gas concentration at zero? N/A
Sickle Cell Disease
Measure Name:

Lung Function - Diffusion Capacity

Release Date:

July 30, 2015


Clinical assessment to determine the capacity of an individual’s lung to exchange gases (e.g., oxygen and carbon dioxide) across the alveolar-capillary interface.


This measure is used to assess the structural and functional properties of the lung and can detect and quantify symptoms associated with conditions that impact the lung, such as sickle cell disease, cystic fibrosis, and obstructive airways disease.


Lung function, lung volume, lung physiology, diffusion capacity, DLCO, functional residual capacity, FRC, sickle cell disease, SCD, emphysema, cystic fibrosis, CF, asbestosis, lupus, arthritis, smoking, sarcoidosis, carbon monoxide, obstructive airway disease, pulmonary, asthma, sleep apnea, breathing