What is LCI?

LCI is a measure of ventilation distribution in the lungs. It is a very sensitive estimate of small airway function in a simple manner. It equals the number of times the patient needs to replace the lung volume to decrease the concentration of a blood insoluble tracer gas in the lungs by a factor of 40 in normal breathing at rest. The tracer gas is recorded during a multiple breath washout (MBW) test.

Why measure LCI?

LCI is a more sensitive marker of abnormalities than FEV1, allowing early detection of disease in the smaller airways, down to small children and infants. It is particularly useful in the preschool group as patients in this age group may be too young to perform acceptable and reproducible forced expiratory maneuvers.

Why use SF6 and not N2 MBW?

  • No influence of N2 back-diffusion into the lungs from blood and tissues
  • No impact of pure O2 on breathing pattern or gas exchange
  • Considerably shorter testing time
  • Less sensitivity to leaks

Why choose INNOCOR LCI?

We use a fast-responding photoacoustic infrared gas analyzer with unmatched sensitivity, accuracy and stability.

Our patented method makes the test significantly shorter, with minimal use of SF6 compared to conventional methods. In case of manoeuvre failure (e.g. coughing or leaks) there is no need to wait – simply repeat the test.

Both the device and the SF6 gas are FDA cleared and CE marked, readily available for both research and clinical use.



The INNOCOR LCI technology is based on the combination of an extremely sensitive Photoacoustic Spectroscopy (PAS) gas analyzer and advanced computer models of gas transport in the human lungs.

In the true LCI test, the patient is breathing a low concentration of a blood insoluble tracer gas, SF6. During washout the patient is breathing air and the SF6 concentration is followed until it reaches 1/40 of the concentration at the end of washin. At this point, the LCI point, the total expired volume recorded during washout is calculated and it is divided by the lung volume. This is by definition Lung Clearance Index, LCI. In other words, the LCI is the number of times the patient needs to replace his lung volume to decrease the tracer gas concentration by a factor of 40. A patient with unequal distribution of ventilation has significantly higher LCI than a normal subject.

The advantages of the true LCI test compared to the conventional FEV1 test are primarily:

  1. The test is performed without special breathing maneuvers and can therefore be applied to the preschool age group.
  2. Unlike FEV1, LCI is dependent not only on convective gas flow but also on gas transport by diffusion. The test is therefore also sensitive to abnormalities in the small airways and thus typically abnormal earlier in a disease than FEV1.



Our LCI technology is implemented in the product Innocor, which meets the Guidelines of the ERS/ATS Concensus Statement. Innocor is very easy to use and the operator needs to be trained only 1 – 2 hours by one of our specialists. It requires very few calibration procedures and patient compliance is easily obtained. The system is particularly suited for use in the preschool age group because of very low dead space and fast response time.

Product data sheet INNOCOR LCI



The specifications compared to the Guidelines:





Small Airway Disease in Pulmonary Hypertension-Additional Diagnostic Value of Multiple Breath Washout and Impulse Oscillometry.
Trinkmann F, Gawlitza J, Künstler M, Schäfer J, Schroeter M, Michels JD, Stach K, Dösch C, Saur, Borggrefe M, Akin I
J Clin Med. 2018 Dec 9;7(12). pii: E532. doi: 10.3390/jcm7120532.

Difference between SF6 and N2 Multiple Breath Washout kinetics is due to N2 back diffusion and error in N2 offset.
Guglani L, Kasi A, Starks M, Pedersen KE, Nielsen JG, Weiner, DJ
J Appl Physiol (1985). 2018 Jul 26. doi: 10.1152/japplphysiol.00326.2018

Impact of leaks in sulfur hexafluoride and nitrogen multiple-breath washout systems.
Jørgen G. Nielsen
ERJ Open Res. 2018 Oct; 4(4): 00119-2018.

Nitrogen back-diffusion during multiple-breath washout with 100% oxygen.
Sullivan L, Forno E, Pedersen K, Nielsen JG, Weiner DJ.
Eur Respir J. 2017 Sep 9;50(3). pii: 1700679. doi: 10.1183/13993003.00679-2017.

Infant lung function: first report of a novel infant multiple breath washout

Shawcross A, Murray C, Aurora P, Horsley A.
Journal of Cystic Fibrosis. Jun 2015, Vol 14, suppl 1, Page S48.

Enhanced photoacoustic gas analyser response time and impact on accuracy at fast ventilation rates during multiple breath washout.
Horsley A, Macleod K, Gupta R, Goddard N, Bell N.
PLoS One. 2014 Jun 3;9(6).

Improving the multiple breath washout test: closed circuit washin with a novel
bolus gas delivery system substantially reduces washin time and does not alter washout.

Horsley A.
Journal of Cystic Fibrosis. Vol. 13, S79 June, 2014.

Lung clearance index in adults with non-cystic fibrosis bronchiectasis.
Gonem S, Scadding A, Soares M, Singapuri A, Gustafsson P, Ohri C, Range S, Brightling CE, Pavord I, Horsley A, Siddiqui S.
Respir Res. 2014 May 18;15:59.

Lung clearance index is a repeatable and sensitive indicator of radiological changes in bronchiectasis.
Rowan SA, Bradley JM, Bradbury I, Lawson J, Lynch T, Gustafsson P, Horsley A, O’Neill K, Ennis M, Elborn JS.
Am J Respir Crit Care Med. 2014 Mar 1;189(5):586-92.

Validation of a photoacoustic gas analyser for the measurement of functional
residual capacity using multiple-breath inert gas washout.

Gonem S, Singer F, Corkill S, Singapur A, Siddiqui S, Gustafsson P.
Respiration. 2014;87(6):462-8.

Lung clearance index: should we really go back to nitrogen washout?
Nielsen JG.
Eur Respir J. 2014 Feb;43(2):655-6.

Age and height dependence of lung clearance index and functional residual

Lum S, Stocks J, Stanojevic S, Wade A, Robinson P, Gustafsson P, Brown M, Aurora P, Subbarao P, Hoo AF, Sonnappa S.
Eur Respir J. 2013 Jun;41(6):1371-7.

Assessment of clinical response to ivacaftor with lung clearance index in cystic
fibrosis patients with a G551D-CFTR mutation and preserved spirometry:
a randomised controlled trial.

Davies J, Sheridan H, Bell N, Cunningham S, Davis SD, Elborn JS, Milla CE, Starner TD, Weiner DJ, Lee PS, Ratjen F
Lancet Respir Med. 2013 Oct;1(8):630-8. Epub 2013 Sep 10.

Consensus statement for inert gas washout measurement using multiple- and
single- breath tests.

Robinson PD, Latzin P, Verbanck S, Hall GL, Horsley A, Gappa M, Thamrin C, Arets HG, Aurora P, Fuchs SI, King GG, Lum S, Macleod K, Paiva M, Pillow JJ, Ranganathan S, Ratjen F, Singer F, Sonnappa S, Stocks J, Subbarao P, Thompson BR, Gustafsson PM.
Eur Respir J. 2013 Mar;41(3):507-22.

Evaluation of the impact of alveolar nitrogen excretion on indices derived from
multiple breath nitrogen washout.

Nielsen N, Nielsen JG, Horsley AR.
PLoS One. 2013 Sep 9;8(9).

Lung clearance index is a sensitive, repeatable and practical measure of airways
disease in adults with cystic fibrosis.

Horsley AR, Gustafsson PM, Macleod KA, Saunders C, Greening AP, Porteous DJ, Davies JC, Cunningham S, Alton EW, Innes JA.
Thorax. 2008 Feb;63(2):135-40.




1. Is the device FDA approved and CE marked?
Yes, both the device and the SF6 (an integral part of the device) are FDA approved (FDA clearance) and CE marked (CE mark).

2. Is the SF6 gas FDA approved?
Yes, the SF6 gas is an integral part of the device.
Our patented technology requires infinitely small amounts of SF6 to be used compared to traditional methods. All concerns regarding the potential greenhouse effect due to the use of SF6 gas have been revoked, read here. The amount of SF6 used per test corresponds to driving half a mile in an economy car.

3. Is the SF6 gas readily available?
The gas can be ordered through our US office for US and Canadian customers and in our Danish HQ for Rest of the World. The usual delivery time in the US is a few working days, depending on geographical area, up to 7 working days in the Rest of the World.
The shelf-life is minimum 1 year from the date of delivery, depending on the manufacturing date this can be often longer.
One gas bottle is typically used for 150-200 LCI tests.

4. Is SF6 sensitive to inspiratory leaks?
No. The impact of inspiratory leaks in SF6 MBW systems is entirely different from N2 MBW, because SF6 is washed out with air. Therefore, an inspiratory leak does not affect the SF6 concentration, but only inspiratory flow, which is not used to calculate FRC or LCI. Consequently, the SF6 MBW method is insensitive to inspiratory leaks.

5. How long time does it take to train an operator?
A typical training is a 1-1½ hour initial session to be familiar with the system and method, followed by a 1-hour session to clarify questions after first hands-on use. Please see the training agenda for further information.
Our design allows for remote online installation and training – this is offered free of charge within the first year of life of the device.
We do regular follow-ups after installation, every 1st, 3rd and 6th and 9th month, to ensure you have been trained and can use the device comfortably.

6. How often do I need to calibrate the device?
The Innocor is calibrated once a day. The flow is calibrated using a 1- or 3-liter syringe and the oxygen signal using ambient air. This takes typical less than 5 minutes. The flow-gas delay is automatically determined during the MBW test.
The device needs to be factory calibrated at our HQ in Denmark once a year. The device will automatically remind you 1 month ahead of the upcoming calibration – once you contacted us we will schedule the work order and send you a quote. All you need is to pack the device and have it ready for pick-up.

7. Are service contracts available?
Yes, service contracts are available and are specific to the models you have purchased. We also offer extended warranty contracts. Standard warranty on parts and workmanship is 12 months.

8. Do you have distributors or agents?
No. We operate from our US office for North America and Canada, and from our HQ in Denmark. Our product specialists’ expertise is readily available online – we prefer the direct method, to offer direct access to our knowledge and know and support our customers the fastest and most efficient way.

9. How do I order consumables and accessories?
Please see a list of our consumables and accessories here. Send us an email at info@pulmotrace.com with the requested part # and we will contact you with a quote.



PulmoTrace is a spin-out from Innovision ApS, a Danish company with roots in space technology. We have over 30 years’ experience in developing medical equipment using advanced gas exchange methods. Our key technology is used to improve diagnostics and management of patients with various pulmonary diseases including Cystic Fibrosis, Asthma and COPD.





















(+45) 63 10 06 20 (GMT+1)

Knud holds an MSc degree in Electrical and Biomedical Engineering. He has more than 25 years experience with respiratory gas analysis, advanced gas exchange methods and design and development of medical products for use in clinical environments and manned space flights.




(+45) 20 78 91 40 (GMT+1) or
(+1) 404 769 0588 (GMT-5)

Jørgen is an MD and PhD in Gas Exchange Physiology. He founded Innovision in 1986 and two other Danish companies (Damec and PAS Technology) that have both been sold to industrial investors. Jørgen has published 40 papers in peer reviewed journals relating to various gas exchange methods including mathematical modelling and in vivo validations. Pubmed entrance is J. Grønlund. Jørgen is also the author of several issued and pending patents.




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PulmoTrace ApS
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Tel. +45 65 95 91 00
Fax +45 65 95 78 00

PulmoTrace, Inc.
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Atlanta, GA 30326, USA
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