Direct challenge tests: Airway hyperresponsiveness in asthma: its measurement and clinical significance. 2010

Donald W Cockcroft
Department of Medicine, Division of Respirology, Critical Care and Sleep Medicine, Royal University Hospital, University of Saskatchewan, Saskatoon, SK, Canada. don.cockcroft@usask.ca

Direct bronchoprovocation challenges (eg, methacholine), which act directly on a specific airway smooth muscle receptor, are the most commonly performed challenge tests. Cut points have been arbitrarily selected to give high sensitivity and negative predictive values. In subjects with clinically current symptoms (within a few days) who inhale methacholine without deep inhalations, a normal methacholine test (provocative concentration causing a 20% fall in FEV(1) [PC(20)] > 16 mg/mL) rules out (current) asthma with reasonable certainty. A positive test in the moderate or greater range (PC(20) < 1 mg/mL) has high specificity and positive predictive value, comparable to the indirect challenges. Values between these levels are consistent with, but not diagnostic of, asthma. The positive predictive value (for clinical asthma) will increase the closer the PC(20) is to 1 mg/mL, the higher the pretest probability is for asthma and the more the methacholine-induced symptoms resemble the naturally occurring symptoms. Direct challenges are more sensitive and less specific than indirect challenges (exercise, adenosine monophosphate, mannitol, etc).

UI MeSH Term Description Entries
D011237 Predictive Value of Tests In screening and diagnostic tests, the probability that a person with a positive test is a true positive (i.e., has the disease), is referred to as the predictive value of a positive test; whereas, the predictive value of a negative test is the probability that the person with a negative test does not have the disease. Predictive value is related to the sensitivity and specificity of the test. Negative Predictive Value,Positive Predictive Value,Predictive Value Of Test,Predictive Values Of Tests,Negative Predictive Values,Positive Predictive Values,Predictive Value, Negative,Predictive Value, Positive
D001985 Bronchial Provocation Tests Tests involving inhalation of allergens (nebulized or in dust form), nebulized pharmacologically active solutions (e.g., histamine, methacholine), or control solutions, followed by assessment of respiratory function. These tests are used in the diagnosis of asthma. Allergen Bronchial Provocation Tests,Allergen Challenge, Endobronchial,Antigen Bronchial Provocation Tests,Bronchial Allergen Challenge,Bronchial Challenge Tests,Inhalation Provocation Tests,Provocation Tests, Bronchial,Endobronchial Challenge Tests,Allergen Challenge, Bronchial,Allergen Challenges, Bronchial,Allergen Challenges, Endobronchial,Bronchial Allergen Challenges,Bronchial Challenge Test,Bronchial Provocation Test,Challenge Test, Bronchial,Challenge Test, Endobronchial,Challenge Tests, Bronchial,Challenge Tests, Endobronchial,Challenge, Bronchial Allergen,Challenge, Endobronchial Allergen,Challenges, Bronchial Allergen,Challenges, Endobronchial Allergen,Endobronchial Allergen Challenge,Endobronchial Allergen Challenges,Endobronchial Challenge Test,Inhalation Provocation Test,Provocation Test, Bronchial,Provocation Test, Inhalation,Provocation Tests, Inhalation,Test, Bronchial Challenge,Test, Bronchial Provocation,Test, Endobronchial Challenge,Test, Inhalation Provocation,Tests, Bronchial Challenge,Tests, Bronchial Provocation,Tests, Endobronchial Challenge,Tests, Inhalation Provocation
D005541 Forced Expiratory Volume Measure of the maximum amount of air that can be expelled in a given number of seconds during a FORCED VITAL CAPACITY determination . It is usually given as FEV followed by a subscript indicating the number of seconds over which the measurement is made, although it is sometimes given as a percentage of forced vital capacity. Forced Vital Capacity, Timed,Timed Vital Capacity,Vital Capacity, Timed,FEVt,Capacities, Timed Vital,Capacity, Timed Vital,Expiratory Volume, Forced,Expiratory Volumes, Forced,Forced Expiratory Volumes,Timed Vital Capacities,Vital Capacities, Timed,Volume, Forced Expiratory,Volumes, Forced Expiratory
D006801 Humans Members of the species Homo sapiens. Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000280 Administration, Inhalation The administration of drugs by the respiratory route. It includes insufflation into the respiratory tract. Drug Administration, Inhalation,Drug Administration, Respiratory,Drug Aerosol Therapy,Inhalation Drug Administration,Inhalation of Drugs,Respiratory Drug Administration,Aerosol Drug Therapy,Aerosol Therapy, Drug,Drug Therapy, Aerosol,Inhalation Administration,Administration, Inhalation Drug,Administration, Respiratory Drug,Therapy, Aerosol Drug,Therapy, Drug Aerosol
D001249 Asthma A form of bronchial disorder with three distinct components: airway hyper-responsiveness (RESPIRATORY HYPERSENSITIVITY), airway INFLAMMATION, and intermittent AIRWAY OBSTRUCTION. It is characterized by spasmodic contraction of airway smooth muscle, WHEEZING, and dyspnea (DYSPNEA, PAROXYSMAL). Asthma, Bronchial,Bronchial Asthma,Asthmas
D012720 Severity of Illness Index Levels within a diagnostic group which are established by various measurement criteria applied to the seriousness of a patient's disorder. Illness Index Severities,Illness Index Severity
D016084 Bronchoconstriction Narrowing of the caliber of the BRONCHI, physiologically or as a result of pharmacological intervention. Bronchial Constriction,Bronchial Constrictions,Bronchoconstrictions,Constriction, Bronchial,Constrictions, Bronchial
D016085 Bronchoconstrictor Agents Agents causing the narrowing of the lumen of a bronchus or bronchiole. Bronchial-Constricting Agents,Bronchoconstrictor Effect,Bronchoconstrictor Effects,Bronchoconstrictors,Agents, Bronchial-Constricting,Agents, Bronchoconstrictor,Bronchial Constricting Agents,Effect, Bronchoconstrictor,Effects, Bronchoconstrictor
D016210 Methacholine Chloride A quaternary ammonium parasympathomimetic agent with the muscarinic actions of ACETYLCHOLINE. It is hydrolyzed by ACETYLCHOLINESTERASE at a considerably slower rate than ACETYLCHOLINE and is more resistant to hydrolysis by nonspecific CHOLINESTERASES so that its actions are more prolonged. It is used as a parasympathomimetic bronchoconstrictor agent and as a diagnostic aid for bronchial asthma. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1116) Methacholine,2-(Acetyloxy)-N,N,N-trimethyl-1-propanaminium Chloride,Acetyl-2-methylcholine Chloride,Acetyl-beta-methacholine Chloride,Acetyl-beta-methylcholine,Mecholine,Mecholyl,Provocholine,Provokit,Acetyl 2 methylcholine Chloride,Acetyl beta methacholine Chloride,Acetyl beta methylcholine,Chloride, Methacholine

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