Table 1

Characteristics of included studies

First authorYearCountryAge group (range years or mean and SD)nPrevalenceFENO measurement deviceCut-off level (ppb)Reference standardKey studyTrue positive*False negative*False positive*True negative*
Arora202006USAAdults (17–38)1720.80NIOX—no further specification17Bronchial provocationYes87511420
Cordeiro212011NetherlandsMainly adults (7–87)1140.37NIOX Flex (c)27FEV1/VC+reversibility and bronchial provocationYes339666
ElHalawani222003USAAdults (18–40)490.14Sievers 280 (c)12Exercise challengeNo70†2913
Florentin232014FranceYoung adults (mean 25 SD 3)1780.11NIOX Mino (e)10.5FEV1/VC+reversibility and PEF variabilityNo1367089
Fortuna242007SpainAdults (18–64)500.44SIR N-6008 (c)20Bronchial provocationYes1751018
Fukuhara252011JapanAdults (48–66)610.69NA623N (c)40FEV1/VC (+reversibility), bronchial provocation, sputum eosinophiliaNo339217
Giovannini262014ItalyMainly adults (mean 38 SD 15)420.50HypAir FENO (e)30Bronchial provocationNo3180†21
Heffler272006ItalyMainly adults (11–75)480.38NIOX Flex (c)36FEV1/VC+reversibility and bronchial provocationNo1441218
Katsoulis282013GreeceAdults (22–37)1120.43NIOX Mino (e)32Bronchial provocationNo23251054
Kostikas292008GreeceYoung adults (mean 21 SD 2)1490.42NIOX Mino (e)19FEV1/VC+reversibility, bronchial provocationNo33301373
Kowal302009PolandAdults (18–45)5400.33Sievers 280i (c)40FEV1/VC+reversibility, bronchial provocation, PEF variability, expert's opinionNo1572163299
Linkosalo312012FinlandChildren (6–19)300.60Sievers 280 (c)20Free running testNo135210
Malinovschi32
 Never smokers2012DenmarkMainly adults (14–44)1080.42NIOX Mino (e)15Expert's assessment based on FEV1/VC+reversibility, bronchial provocation and medication useNo18141466
 Ex-smokers620.3122127637
 Current smokers1120.291735102340
Pedrosa332010SpainAdults (mean 34 SD 13)1140.31NIOX Mino (e)40Bronchial provocationNo2692257
Pizzimenti342009ItalyNot stated (probably adults)1560.09NIOX Mino (e)55Bronchial challenge, spirometryNo11317125
Sato352008JapanAdults (20–78)710.68Kimoto, Osaka, Japan (c)38.8FEV1/VC (+reversibility) and/or bronchial provocation, symptomsYes3810221
Schleich362012BelgiumAdults (mean 41 SD 16)1740.47NIOX Flex (c)34Bronchial provocationNo2953488
Schneider372013GermanyMainly adults (mean 43)3930.39NIOX Mino (e)25FEV1/VC+reversibility and bronchial provocationYes757960179
Sivan382009IsraelChildren (5–18)1130.61Eco Physics CLD88 (c)19Expert assessment based on FEV1/VC (+reversibility) and/or bronchial provocation, medicationYes5910539
Smith392004New ZealandMainly adults (9–72)470.36Logan LR2000 (c)20FEV1/VC+reversibility, bronchial provocationYes152624
Smith402005New ZealandMainly adults (14–71)520.52NIOX Flex (c)47FEV1/FVC reversibility, meta-choline challenge, ICS responseNo1512223
Tilemann412011GermanyAdults (38–58)2100.41NIOX Mino (e)46Bronchial provocation or reversibilityYes256110114
Voutilainen422013FinlandAdolescents and adults (14–31)870.34NIOX Flex (c)30Expert's assessment based on FEV1/VC+ reversibility, bronchial provocation, PEF variabilityNo1317651
Wang43
– Bronchodilatation2015ChinaMainly adults (13–89)5150.35Nano Coulomb
NO analyser, Shangwo (u)
41Depending on FEV1 predicted positive bronchodilatation or bronchial provocationNo1345183247
–Bronchial provocation4080.3164656016327
Woo442012KoreaChildren (8–16)2450.68NIOX Mino (e)21FEV1/VC+ reversibility and bronchial provocationNo95721068
Zhang452011ChinaAdults (15–70)1060.37NIOX Mino (e)40FEV1 with bronchodilator, bronchial challenge testYes2910958
  • *Values are absolute frequencies.

  • †In studies (data sets) in which a cell in the contingency table was empty, a continuity correction of 0.5 was used for data analyses.

  • c, chemoluminescence; e, electrochemical; ICS, inhaled corticoid steroids; PEF, peak expiratory flow rate; reversibility, positive reaction to a bronchodilator; u, unclear; VC, vital capacity.