TLC	Total lung capacity: the volume in the lungs at maximal inflation
RV	Residual volume: the volume of air remaining in the lungs after a maximal exhalation
ERV	Expiratory reserve volume: the maximal volume of air that can be exhaled from the end-expiratory position
IRV	Inspiratory reserve volume: the maximal volume that can be inhaled from the end-inspiratory level
IC	Inspiratory capacity: the sum of IRV and TV
IVC	Inspiratory vital capacity: the maximum volume of air inhaled from the point of maximum expiration
VC	Vital capacity: the volume equal to TLC − RV
VT	Tidal volume: that volume of air moved into or out of the lungs during quiet breathing (VT indicates a subdivision of the lung; when tidal volume is precisely measured, as in gas exchange calculation, the symbol VT or VT is used.)
FRC	Functional residual capacity: the volume in the lungs at the end-expiratory position
RV/TLC%	Residual volume expressed as percent of TLC
VA	Alveolar gas volume
VL	Actual volume of the lung including the volume of the conducting airway.
FVC	Forced vital capacity: the determination of the vital capacity from a maximally forced expiratory effort
FEV1	Volume that has been exhaled at the end of the first second of forced expiration
FEFx	Forced expiratory flow related to some portion of the FVC curve; modifiers refer to amount of FVC already exhaled
FEFmax	The maximum instantaneous flow achieved during a FVC maneuver
FIF	Forced inspiratory flow: (Specific measurement of the forced inspiratory curve is denoted by nomenclature analogous to that for the forced expiratory curve. For example, maximum inspiratory flow is denoted FIFmax. Unless otherwise specified, volume qualifiers indicate the volume inspired from RV at the point of measurement.)
PEF	The highest forced expiratory flow measured with a peak flow meter
MVV	Maximal voluntary ventilation: volume of air expired in a specified period during repetitive maximal effort
v t e

Pulmonary Function Testing (PFT) is a complete evaluation of the respiratory system including patient history, physical examinations, chest x-ray examinations, arterial blood gas analysis, and tests of pulmonary function. The primary purpose of pulmonary function testing is to identify the severity of pulmonary impairment.^[1] Pulmonary function testing has diagnostic and therapeutic roles and helps clinicians answer some general questions about patients with lung disease. PFT's are performed by a Pulmonary scientist who typically holds credentialing as a Registered Pulmonary Function Technician, a Certified Pulmonary Function Technician or a Registered Respiratory Therapist.

Indications[link]

Pulmonary function testing is a diagnostic and management tool used for a variety of reasons.

Pediatric neuromuscular disorders[link]

Neuromuscular disorders such as Duchenne muscular dystrophy are associated with gradual loss of muscle function over time. Involvement of respiratory muscles results in poor ability to cough and decreased ability to breathe well and leads to atelectasis (the inability of the lungs to gain oxygen) and an overall insufficency in lung strength.^[2] A combination of reduced lung compliance caused by generalized and widespread microatelectasis and chest wall deformity caused by increased chest wall compliance4 results in increased work of breathing and chronic respiratory insufficiency.^[3] Musculoskeletal deformities such as kyphoscoliosis contribute to restrictive lung disease.

Pulmonary function testing in patients with neuromuscular disorders helps to evaluate the respiratory status of patients at the time of diagnosis, monitor their progress and course, evaluate them for possible surgery, and gives an overall idea of the prognosis.^[4]

Other indications[link]

• Chronic dyspnea
• Asthma
• Chronic obstructive pulmonary disease
• Restrictive lung disease
• Preoperative testing
• Impairment or disability

Spirometry[link]

Spirometry includes tests of pulmonary mechanics – measurements of FVC, FEV₁, FEF values, forced inspiratory flow rates (FIFs), and MVV. Measuring pulmonary mechanics assesses the ability of the lungs to move large volumes of air quickly through the airways to identify airway obstruction.

The measurements taken by the spirometry device are used to generate a pneumotachograph that can help to assess lung conditions such as: asthma, pulmonary fibrosis, cystic fibrosis, and chronic obstructive pulmonary disease. Physicians may also use the test results to diagnose bronchial hyperresponsiveness to exercise, cold air, or pharmaceutical agents.^[5]

Complications Spirometry is a safe procedure; however, there is cause for concern regarding untoward reactions. The value of the test data should be weighed against potential hazards. Some complications have been reported, including pneumothorax, increased intracranial pressure, syncope, chest pain, paroxysmal coughing, nosocomial infections, oxygen desaturation, and bronchospasm.

Measurements[link]

There are four lung volumes and four lung capacities. A lung capacity consists of two or more lung volumes. The lung volumes are tidal volume (V_T), inspiratory reserve volume (IRV), expiratory reserve volume (ERV), and residual volume (RV). The four lung capacities are total lung capacity (TLC), inspiratory capacity (IC), functional residual capacity (FRC) and vital capacity (VC).

Maximal respiratory pressures[link]

Measurement of maximal inspiratory and expiratory pressures is indicated whenever there is an unexplained decrease in vital capacity or respiratory muscle weakness is suspected clinically. Maximal inspiratory pressure (MIP) is the maximal pressure that can be produced by the patient trying to inhale through a blocked mouthpiece. Maximal expiratory pressure (MEP) is the maximal pressure measured during forced expiration (with cheeks bulging) through a blocked mouthpiece after a full inhalation. Repeated measurements of MIP and MEP are useful in following the course of patients with neuromuscular disorders.

Diffusing capacity[link]

Measurement of the single-breath diffusing capacity for carbon monoxide (DLCO) is a fast and safe tool in the evaluation of both restrictive and obstructive lung disease.

Oxygen desaturation during exercise[link]

The six-minute walk test is a good index of physical function and therapeutic response in patients with chronic lung disease, such as COPD or idiopathic pulmonary fibrosis^[6][7][8]

Arterial blood gases[link]

Arterial blood gases (ABGs) are a helpful measurement in pulmonary function testing in selected patients. The primary role of measuring ABGs in individuals that are healthy and stable is to confirm hypoventilation when it is suspected on the basis of medical history, such as respiratory muscle weakness or advanced COPD.

An elevated serum bicarbonate level, or chronic hypoxemia. ABGs also provide a more detailed assessment of the severity of hypoxemia in patients who have low normal oxyhemoglobin saturation.

Helium Dilution[link]

The helium dilution technique for measuring lung volumes uses a closed, rebreathing circuit.^[9] This technique is based on the assumptions that a known volume and concentration of helium in air begin in the closed spirometer, that the patient has no helium in their lungs, and that an equilibration of helium can occur between the spirometer and the lungs.

Nitrogen Washout[link]

The nitrogen washout technique uses a non-rebreathing open circuit. The technique is based on the assumptions that the nitrogen concentration in the lungs is 78% and in equilibrium with the atmosphere, that the patient inhales 100% oxygen and that the oxygen replaces all of the nitrogen in the lungs.^[10]

Plethysmography[link]

The plethysmography technique applies Boyle's law and uses measurements of volume and pressure changes to determine lung volume, assuming temperature is constant.^[11]

Significance[link]

Changes in lung volumes and capacities are generally consistent with the pattern of impairment. TLC, FRC and RV increase with obstructive lung diseases and decrease with restrictive impairment.

References[link]

1. ^ Pulmonary terms and symbols: a report of the ACCP-ATS Joint Committee on Pulmonary Nomenclature, Chest 67:583, 1975
2. ^ Finder JD, Birnkrant D, Carl J, et al. Respiratory care of the patients with Duchenne muscular dystrophy: ATS consensus statement. Am J Respir Crit Care Med.2004;170 (4):456– 465
3. ^ Wang CH, Finkel RS, Bertini ES, et al. Consensus statement for standard of care in spinal muscular atrophy. J Child Neurol.2007;22 (8):1027–1049
4. ^ Sharma GD (2009). "Pulmonary function testing in neuromuscular disorders.". Pediatrics 123 Suppl 4: S219-21. DOI:10.1542/peds.2008-2952D. PMID 19420147. http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=19420147. 
5. ^ Pulmonary Function Test in New York, Article. June 2010. Dr. Marina Gafanovich, MD - 1550 York Ave, New York NY 10028 - (212) 249-6218. NYC Pulmonary FUnction Test
6. ^ Enright PL (2003). "The six-minute walk test.". Respir Care 48 (8): 783–5. PMID 12890299. 
7. ^ Swigris JJ, Wamboldt FS, Behr J, du Bois RM, King TE, Raghu G et al. (2010). "The 6 minute walk in idiopathic pulmonary fibrosis: longitudinal changes and minimum important difference.". Thorax 65 (2): 173–7. DOI:10.1136/thx.2009.113498. PMC 3144486. PMID 19996335. //www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3144486. 
8. ^ ATS Committee on Proficiency Standards for Clinical Pulmonary Function Laboratories (2002). "ATS statement: guidelines for the six-minute walk test.". Am J Respir Crit Care Med 166 (1): 111–7. PMID 12091180. 
9. ^ Hathirat S, Renzetti AD, Mitchell M: Measurement of the total lung capacity by helium dilution in a constant volume system, Am Rev Respir Dis 102:760, 1970.
10. ^ Boren HG, Kory RC, Snyder JC: The veterans Administration-Army cooperative study of pulmonary function, II: the lung volume and its subdivisions in normal men, Am J Med 41:96, 1966.
11. ^ Dubois AB, et al: A rapid plethysmographic method for measuring thoracic gas volume: a comparison with a nitrogen washout method for measure FRC in normal patients, J Clin Invest 35:322, 1956.

Function test (or functional test) can refer to:

• Thyroid function tests
• Liver function tests
• Lung function test
• Functional testing

This disambiguation page lists articles associated with the same title. If an internal link led you here, you may wish to change the link to point directly to the intended article.

TLC	Total lung capacity: the volume in the lungs at maximal inflation
RV	Residual volume: the volume of air remaining in the lungs after a maximal exhalation
ERV	Expiratory reserve volume: the maximal volume of air that can be exhaled from the end-expiratory position
IRV	Inspiratory reserve volume: the maximal volume that can be inhaled from the end-inspiratory level
IC	Inspiratory capacity: the sum of IRV and TV
IVC	Inspiratory vital capacity: the maximum volume of air inhaled from the point of maximum expiration
VC	Vital capacity: the volume equal to TLC − RV
VT	Tidal volume: that volume of air moved into or out of the lungs during quiet breathing (VT indicates a subdivision of the lung; when tidal volume is precisely measured, as in gas exchange calculation, the symbol VT or VT is used.)
FRC	Functional residual capacity: the volume in the lungs at the end-expiratory position
RV/TLC%	Residual volume expressed as percent of TLC
VA	Alveolar gas volume
VL	Actual volume of the lung including the volume of the conducting airway.
FVC	Forced vital capacity: the determination of the vital capacity from a maximally forced expiratory effort
FEV1	Volume that has been exhaled at the end of the first second of forced expiration
FEFx	Forced expiratory flow related to some portion of the FVC curve; modifiers refer to amount of FVC already exhaled
FEFmax	The maximum instantaneous flow achieved during a FVC maneuver
FIF	Forced inspiratory flow: (Specific measurement of the forced inspiratory curve is denoted by nomenclature analogous to that for the forced expiratory curve. For example, maximum inspiratory flow is denoted FIFmax. Unless otherwise specified, volume qualifiers indicate the volume inspired from RV at the point of measurement.)
PEF	The highest forced expiratory flow measured with a peak flow meter
MVV	Maximal voluntary ventilation: volume of air expired in a specified period during repetitive maximal effort
v t e

Spirometry (meaning the measuring of breath) is the most common of the pulmonary function tests (PFTs), measuring lung function, specifically the amount (volume) and/or speed (flow) of air that can be inhaled and exhaled. Spirometry is an important tool used for generating pneumotachographs, which are helpful in assessing conditions such as asthma, pulmonary fibrosis, cystic fibrosis, and COPD.

Spirometry testing[link]

A modern ultrasound based desktop spirometer.

A modern portable desktop spirometer with digital turbine and antibacterial filter

Device for spirometry. The patient places his or her lips around the blue mouthpiece. The teeth go between the nubs and the shield, and the lips go over the shield. A noseclip guarantees that breath will flow only through the mouth.

Screen for spirometry readouts at right. The chamber can also be used for body plethysmography.

The spirometry test is performed using a device called a spirometer, which comes in several different varieties. Most spirometers display the following graphs, called spirograms:

• a volume-time curve, showing volume (liters) along the Y-axis and time (seconds) along the X-axis
• a flow-volume loop, which graphically depicts the rate of airflow on the Y-axis and the total volume inspired or expired on the X-axis

Procedure[link]

The basic forced volume vital capacity (FVC) test varies slightly depending on the equipment used.

Generally, the patient is asked to take the deepest breath they can, and then exhale into the sensor as hard as possible, for as long as possible, preferably at least 6 seconds. It is sometimes directly followed by a rapid inhalation (inspiration), in particular when assessing possible upper airway obstruction. Sometimes, the test will be preceded by a period of quiet breathing in and out from the sensor (tidal volume), or the rapid breath in (forced inspiratory part) will come before the forced exhalation.

During the test, soft nose clips may be used to prevent air escaping through the nose. Filter mouthpieces may be used to prevent the spread of microorganisms.

Limitations of test[link]

The maneuver is highly dependent on patient cooperation and effort, and is normally repeated at least three times to ensure reproducibility. Since results are dependent on patient cooperation, FVC can only be underestimated, never overestimated.

Due to the patient cooperation required, spirometry can only be used on children old enough to comprehend and follow the instructions given (6 years old or more), and only on patients who are able to understand and follow instructions — thus, this test is not suitable for patients who are unconscious, heavily sedated, or have limitations that would interfere with vigorous respiratory efforts. Other types of lung function tests are available for infants and unconscious persons.

Another major limitation is the fact that many intermittent or mild asthmatics have normal spirometry between acute exacerbation, limiting spirometry's usefulness as a diagnostic. It is more useful as a monitoring tool: a sudden decrease in FEV1 or other spirometric measure in the same patient can signal worsening control, even if the raw value is still normal. Patients are encouraged to record their personal best measures.

Related tests[link]

Spirometry can also be part of a bronchial challenge test, used to determine bronchial hyperresponsiveness to either rigorous exercise, inhalation of cold/dry air, or with a pharmaceutical agent such as methacholine or histamine.

Sometimes, to assess the reversibility of a particular condition, a bronchodilator is administered before performing another round of tests for comparison. This is commonly referred to as a reversibility test, or a post bronchodilator test (Post BD), and is an important part in diagnosing asthma versus COPD.

Other complementary lung functions tests include plethysmography and nitrogen washout.

Parameters[link]

The most common parameters measured in spirometry are Vital capacity (VC), Forced vital capacity (FVC), Forced expiratory volume (FEV) at timed intervals of 0.5, 1.0 (FEV1), 2.0, and 3.0 seconds, Forced expiratory flow 25–75% (FEF 25–75) and Maximal voluntary ventilation (MVV),^[1] also known as Maximum breathing capacity.^[2] Other tests may be performed in certain situations.

Results are usually given in both raw data (litres, litres per second) and percent predicted — the test result as a percent of the "predicted values" for the patients of similar characteristics (height, age, sex, and sometimes race and weight). The interpretation of the results can vary depending on the physician and the source of the predicted values. Generally speaking, results nearest to 100% predicted are the most normal, and results over 80% are often considered normal. Multiple publications of predicted values have been published and may be calculated online based on age, sex, weight and ethnicity. However, review by a doctor is necessary for accurate diagnosis of any individual situation.

A bronchodilator is also given in certain circumstances and a pre/post graph comparison is done to assess the effectiveness of the bronchodilator. See the example printout.

Functional residual capacity (FRC) cannot be measured via spirometry, but it can be measured with a plethysmograph or dilution tests (for example, helium dilution test).

Average values for Forced Vital Capacity (FVC), Forced Expiratory Volume in 1 Second (FEV1) and Forced Expiratory Flow 25–75% (FEF25–75%), according to a study in the United States 2007 of 3,600 subjects aged 4–80 years.^[3] Y-axis is expressed in litres for FVC and FEV1, and in litres/second for FEF25–75%.

Forced vital capacity (FVC)[link]

Forced vital capacity (FVC) is the volume of air that can forcibly be blown out after full inspiration, measured in liters. FVC is the most basic maneuver in spirometry tests.

Forced expiratory volume in 1 second (FEV1)[link]

FEV1 is the volume of air that can forcibly be blown out in one second, after full inspiration. Average values for FEV1 in healthy people depend mainly on sex and age, according to the diagram at left. Values of between 80% and 120% of the average value are considered normal.^[4] Predicted normal values for FEV1 can be calculated online and depend on age, sex, height, weight and ethnicity as well as the research study that they are based upon.

FEV1/FVC ratio (FEV1%)[link]

FEV₁/FVC (FEV1%) is the ratio of FEV₁ to FVC. In healthy adults this should be approximately 75–80%. In obstructive diseases (asthma, COPD, chronic bronchitis, emphysema) FEV₁ is diminished because of increased airway resistance to expiratory flow; the FVC may be decreased as well, due to the premature closure of airway in expiration, just not in the same proportion as FEV₁ (for instance, both FEV₁ and FVC are reduced, but the former is more affected because of the increased airway resistance). This generates a reduced value (<80%, often ~45%). In restrictive diseases (such as pulmonary fibrosis) the FEV₁ and FVC are both reduced proportionally and the value may be normal or even increased as a result of decreased lung compliance.

A derived value of FEV1% is FEV1% predicted, which is defined as FEV1% of the patient divided by the average FEV1% in the population for any person of similar age, sex and body composition.

Forced expiratory flow (FEF)[link]

Forced expiratory flow (FEF) is the flow (or speed) of air coming out of the lung during the middle portion of a forced expiration. It can be given at discrete times, generally defined by what fraction remains of the forced vital capacity (FVC). The usual intervals are 25%, 50% and 75% (FEF25, FEF50 and FEF75), or 25% and 50% of FVC. It can also be given as a mean of the flow during an interval, also generally delimited by when specific fractions remain of FVC, usually 25–75% (FEF25–75%). Average ranges in the healthy population depend mainly on sex and age, with FEF25–75% shown in diagram at left. Values ranging from 50-60% and up to 130% of the average are considered normal.^[4] Predicted normal values for FEF can be calculated online and depend on age, sex, height, weight and ethnicity as well as the research study that they are based upon.

MMEF or MEF stands for maximal (mid-)expiratory flow and is the peak of expiratory flow as taken from the flow-volume curve and measured in liters per second. It should theoretically be identical to peak expiratory flow (PEF), which is, however, generally measured by a peak flow meter and given in liters per minute.^[5]

Recent research suggests that FEF25-75% or FEF25-50% may be a more sensitive parameter than FEV1 in the detection of obstructive small airway disease.^[6][7] However, in the absence of concomitant changes in the standard markers, discrepancies in mid-range expiratory flow may not be specific enough to be useful, and current practice guidelines recommend continuing to use FEV1, VC, and FEV1/VC as indicators of obstructive disease.^[8][9]

More rarely, forced expiratory flow may be given at intervals defined by how much remains of total lung capacity. In such cases, it is usually designated as e.g. FEF70%TLC, FEF60%TLC and FEF50%TLC.^[5]

Forced inspiratory flow 25–75% or 25–50%[link]

Forced inspiratory flow 25–75% or 25–50% (FIF 25–75% or 25–50%) is similar to FEF 25–75% or 25–50% except the measurement is taken during inspiration.

Peak expiratory flow (PEF)[link]

Normal values for Peak Expiratory Flow (PEF), shown on EU scale.^[10]

Peak expiratory flow (PEF) is the maximal flow (or speed) achieved during the maximally forced expiration initiated at full inspiration, measured in liters per minute.

Tidal volume (TV)[link]

Tidal volume (TV) is the volume of air inspired or expired in a single breath at rest.

Total lung capacity (TLC)[link]

Total lung capacity (TLC) is the maximum volume of air present in the lungs

Diffusing capacity (DLCO)[link]

Diffusing capacity (or DLCO) is the carbon monoxide uptake from a single inspiration in a standard time (usually 10 sec). Since air consists of very minute or trace quantities of CO, 10 seconds is considered to be the standard time for inhalation, then rapidly blow it out (exhale). The exhaled gas is tested to determine how much of the tracer gas was absorbed during the breath. This will pick up diffusion impairments, for instance in pulmonary fibrosis.^[11] This must be corrected for anemia (because rapid CO diffusion is dependent on hemoglobin in RBC's; a low hemoglobin concentration, anemia, will reduce DLCO) and pulmonary hemorrhage (excess RBC's in the interstitium or alveoli can absorb CO and artificially increase the DLCO capacity). Atmospheric pressure and/or altitude will also affect measured DLCO, and so a correction factor is needed to adjust for standard pressure. Online calculators are available to correct for hemoglobin levels and altitude and/or pressure where the measurement was taken.

Maximum voluntary ventilation (MVV)[link]

Maximum voluntary ventilation (MVV) is a measure of the maximum amount of air that can be inhaled and exhaled within one minute. For the comfort of the patient this is done over a 15 second time period before being extrapolated to a value for one minute expressed as liters/minute. Average values for males and females are 140–180 and 80–120 liters per minute respectively.

[edit] Static lung compliance (C_st)

When estimating static lung compliance, volume measurements by the spirometer needs to be complemented by pressure transducers in order to simultaneously measure the transpulmonary pressure. When having drawn a curve with the relations between changes in volume to changes in transpulmonary pressure, C_st is the slope of the curve during any given volume, or, mathematically, ΔV/ΔP.^[12] Static lung compliance is perhaps the most sensitive parameter for the detection of abnormal pulmonary mechanics.^[13] It is considered normal if it is 60% to 140% of the average value in the population for any person of similar age, sex and body composition.^[4]

In those with acute respiratory failure on mechanical ventilation, "the static compliance of the total respiratory system is conventionally obtained by dividing the tidal volume by the difference between the "plateau" pressure measured at the airway opening (PaO) during an occlusion at end-inspiration and positive end-expiratory pressure (PEEP) set by the ventilator".^[14]

Others[link]

Forced Expiratory Time (FET)
Forced Expiratory Time (FET) measures the length of the expiration in seconds.

Slow vital capacity (SVC)
Slow vital capacity (SVC) is the maximum volume of air that can be exhaled slowly after slow maximum inhalation.

Maximal pressure (P_max and P_i)
P_max is the asymptotically maximal pressure that can be developed by the respiratory muscles at any lung volume and P_i is the maximum inspiratory pressure that can be developed at specific lung volumes.^[15] This measurement also requires pressure transducers in addition. It is considered normal if it is 60% to 140% of the average value in the population for any person of similar age, sex and body composition.^[4] A derived parameter is the coefficient of retraction (CR) which is P_max/TLC .<hedenstrom2009/>

Mean transit time (MTT)
Mean transit time is the area under the flow-volume curve divided by the forced vital capacity.^[16]

Technologies used in spirometers[link]

• Volumetric Spirometers
  • Water bell
  • Bellows wedge
• Flow measuring Spirometers
  • Fleisch-pneumotach
  • Lilly (screen) pneumotach
  • Turbine (actually a rotating vane which spins because of the air flow generated by the subject. The revolutions of the vane are counted as they break a light beam)
  • Pitot tube
  • Hot-wire anemometer
  • Ultrasound

See also[link]

• Peak flow meter
• Nitrogen washout

References[link]

1. ^ surgeryencyclopedia.com > Spirometry tests Retrieved on Mars 14, 2010
2. ^ MVV and MBC
3. ^ Stanojevic S, Wade A, Stocks J, et al. (February 2008). "Reference Ranges for Spirometry Across All Ages: A New Approach". Am. J. Respir. Crit. Care Med. 177 (3): 253–60. DOI:10.1164/rccm.200708-1248OC. PMC 2643211. PMID 18006882. //www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2643211. 
4. ^ ^{a b c d} LUNGFUNKTION — Practice compendium for semester 6. Department of Medical Sciences, Clinical Physiology, Academic Hospital, Uppsala, Sweden. Retrieved 2010.
5. ^ ^{a b} Interpretation model — compendium at Uppsala Academic Hospital. By H. Hedenström. 2009-02-04
6. ^ Simon, Michael R.; Chinchilli, Vernon M., Phillips, Brenda R., Sorkness, Christine A., Lemanske Jr., Robert F., Szefler, Stanley J., Taussig, Lynn, Bacharier, Leonard B., Morgan, Wayne (1 September 2010). "Forced expiratory flow between 25% and 75% of vital capacity and FEV1/forced vital capacity ratio in relation to clinical and physiological parameters in asthmatic children with normal FEV1 values". Journal of Allergy and Clinical Immunology 126 (3): 527–534.e8. DOI:10.1016/j.jaci.2010.05.016. 
7. ^ Ciprandi, Giorgio; Cirillo, Ignazio (1 February 2011). "Forced expiratory flow between 25% and 75% of vital capacity may be a marker of bronchial impairment in allergic rhinitis". Journal of Allergy and Clinical Immunology 127 (2): 549–549. DOI:10.1016/j.jaci.2010.10.053. 
8. ^ Pellegrino, R; Viegi, G, Brusasco, V, Crapo, RO, Burgos, F, Casaburi, R, Coates, A, van der Grinten, CP, Gustafsson, P, Hankinson, J, Jensen, R, Johnson, DC, MacIntyre, N, McKay, R, Miller, MR, Navajas, D, Pedersen, OF, Wanger, J (2005 Nov). "Interpretative strategies for lung function tests". The European respiratory journal : official journal of the European Society for Clinical Respiratory Physiology 26 (5): 948–68. DOI:10.1183/09031936.05.00035205. PMID 16264058. 
9. ^ Kreider, Maryl. "Chapter 14.1 Pulmonary Function Testing". ACP Medicine. Decker Intellectual Properties. http://online.statref.com/Notes/ResolveNote.aspx?NoteID=48177&grpalias=TEX. Retrieved 29 April 2011. 
10. ^ Nunn AJ, Gregg I (April 1989). "New regression equations for predicting peak expiratory flow in adults". BMJ 298 (6680): 1068–70. DOI:10.1136/bmj.298.6680.1068. PMC 1836460. PMID 2497892. //www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1836460.  Adapted by Clement Clarke for use in EU scale — see Peakflow.com ⇒ Predictive Normal Values (Nomogram, EU scale)
11. ^ MedlinePlus Encyclopedia Lung diffusion testing
12. ^ George, Ronald B. (2005). Chest medicine: essentials of pulmonary and critical care medicine. Lippincott Williams & Wilkins. p. 96. ISBN 978-0-7817-5273-2. http://books.google.com/books?id=ZzlX2zJMbdgC. 
13. ^ Sud, A.; Gupta, D.; Wanchu, A.; Jindal, S. K.; Bambery, P. (2001). "Static lung compliance as an index of early pulmonary disease in systemic sclerosis". Clinical rheumatology 20 (3): 177–180. DOI:10.1007/s100670170060. PMID 11434468.  edit
14. ^ Rossi A, Gottfried SB, Zocchi L, et al. (May 1985). "Measurement of static compliance of the total respiratory system in patients with acute respiratory failure during mechanical ventilation. The effect of intrinsic positive end-expiratory pressure". The American review of respiratory disease 131 (5): 672–7. PMID 4003913. 
15. ^ Lausted, C.; Johnson, A.; Scott, W.; Johnson, M.; Coyne, K.; Coursey, D. (2006). "Maximum static inspiratory and expiratory pressures with different lung volumes". Biomedical engineering online 5 (1): 29. DOI:10.1186/1475-925X-5-29. PMC 1501025. PMID 16677384. //www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1501025.  edit [1]
16. ^ Borth, F. M. (1982). "The derivation of an index of ventilatory function from spirometric recordings using canonical analysis". British Journal of Diseases of the Chest 76: 400–756. DOI:10.1016/0007-0971(82)90077-8.  edit

Further reading[link]

• Miller, MR; Crapo R, Hankinson J et al. (July 2005). "General considerations for lung function testing". European Respiratory Journal 26 (1): 153–161. DOI:10.1183/09031936.05.00034505. PMID 15994402. http://erj.ersjournals.com/cgi/content/full/26/1/153. 

External links[link]

• Detailed information on spirometric testing, interpretation and physiology at spirxpert.com
• General information on spirometry at spirometrie.info
• General information on spirometers and spirometry
• American Thoracic Society (ATS)
• European Respiratory Society (ERS)
• General Practice Airways Group