Participating practices Ten practices participated in this study. They served a population of almost 120,000 people, ranging from ~3500 to 48000 registered patients. Geographically, five of the practices were located in inner-city Leicester, three were in surrounding towns, and two were in village locations.

Participants Electronic database searches identified 1548 eligible children; 1097 (71%) were on their GPs asthma register, and 451 (29%) were not, but had received asthma medications in the previous 12 months.

In total 614 children responded to the written invitations and attended clinics held between June 2016 and August 2017; of these, 456 (75%) were on the asthma register. Sixty-three percent of children were recruited in the months of March to August, and the remainder in the months of September to February.

Written informed consent was obtained from carers of 613 children. One parent refused consent and one parent later withdrew their consent without giving a reason, leaving 612 children in total. The characteristics of recruited children are shown in table 1. Overall, the participation rate was 40% of eligible patients, but ranged from 8% to 59% between practices. The practice recruiting only 8% of eligible children was an outlier, and due in part to recruitment at this practice commencing late into the study and therefore fewer clinics (in relation to the practice size) were set up compared with other practices.

Participating practices Ten practices participated in this study. They served a population of almost 120,000 people, ranging from ~3500 to 48000 registered patients. Geographically, five of the practices were located in inner-city Leicester, three were in surrounding towns, and two were in village locations.

Participants Electronic database searches identified 1548 eligible children; 1097 (71%) were on their GPs asthma register, and 451 (29%) were not, but had received asthma medications in the previous 12 months.

In total 614 children responded to the written invitations and attended clinics held between June 2016 and August 2017; of these, 456 (75%) were on the asthma register. Sixty-three percent of children were recruited in the months of March to August, and the remainder in the months of September to February.

Written informed consent was obtained from carers of 613 children. One parent refused consent and one parent later withdrew their consent without giving a reason, leaving 612 children in total. The characteristics of recruited children are shown in table 1. Overall, the participation rate was 40% of eligible patients, but ranged from 8% to 59% between practices. The practice recruiting only 8% of eligible children was an outlier, and due in part to recruitment at this practice commencing late into the study and therefore fewer clinics (in relation to the practice size) were set up compared with other practices.

Participating practices Ten practices participated in this study. They served a population of almost 120,000 people, ranging from ~3500 to 48000 registered patients. Geographically, five of the practices were located in inner-city Leicester, three were in surrounding towns, and two were in village locations.

Participants Electronic database searches identified 1548 eligible children; 1097 (71%) were on their GPs asthma register, and 451 (29%) were not, but had received asthma medications in the previous 12 months.

In total 614 children responded to the written invitations and attended clinics held between June 2016 and August 2017; of these, 456 (75%) were on the asthma register. Sixty-three percent of children were recruited in the months of March to August, and the remainder in the months of September to February.

Written informed consent was obtained from carers of 613 children. One parent refused consent and one parent later withdrew their consent without giving a reason, leaving 612 children in total. The characteristics of recruited children are shown in table 1. Overall, the participation rate was 40% of eligible patients, but ranged from 8% to 59% between practices. The practice recruiting only 8% of eligible children was an outlier, and due in part to recruitment at this practice commencing late into the study and therefore fewer clinics (in relation to the practice size) were set up compared with other practices.

Participating practices Ten practices participated in this study. They served a population of almost 120,000 people, ranging from ~3500 to 48000 registered patients. Geographically, five of the practices were located in inner-city Leicester, three were in surrounding towns, and two were in village locations.

Participants Electronic database searches identified 1548 eligible children; 1097 (71%) were on their GPs asthma register, and 451 (29%) were not, but had received asthma medications in the previous 12 months.

In total 614 children responded to the written invitations and attended clinics held between June 2016 and August 2017; of these, 456 (75%) were on the asthma register. Sixty-three percent of children were recruited in the months of March to August, and the remainder in the months of September to February.

Written informed consent was obtained from carers of 613 children. One parent refused consent and one parent later withdrew their consent without giving a reason, leaving 612 children in total. The characteristics of recruited children are shown in table 1. Overall, the participation rate was 40% of eligible patients, but ranged from 8% to 59% between practices. The practice recruiting only 8% of eligible children was an outlier, and due in part to recruitment at this practice commencing late into the study and therefore fewer clinics (in relation to the practice size) were set up compared with other practices.

Participating practices Ten practices participated in this study. They served a population of almost 120,000 people, ranging from ~3500 to 48000 registered patients. Geographically, five of the practices were located in inner-city Leicester, three were in surrounding towns, and two were in village locations.

Participants Training was delivered to 27 Practice nurses and health care assistants. No staff had previously had training to perform spirometry or FeNO testing in children.

Participating practices Ten practices participated in this study. They served a population of almost 120,000 people, ranging from ~3500 to 48000 registered patients. Geographically, five of the practices were located in inner-city Leicester, three were in surrounding towns, and two were in village locations.

Participants Electronic database searches identified 1548 eligible children; 1097 (71%) were on their GPs asthma register, and 451 (29%) were not, but had received asthma medications in the previous 12 months.

In total 614 children responded to the written invitations and attended clinics held between June 2016 and August 2017; of these, 456 (75%) were on the asthma register. Sixty-three percent of children were recruited in the months of March to August, and the remainder in the months of September to February.

Written informed consent was obtained from carers of 613 children. One parent refused consent and one parent later withdrew their consent without giving a reason, leaving 612 children in total. The characteristics of recruited children are shown in table 1. Overall, the participation rate was 40% of eligible patients, but ranged from 8% to 59% between practices. The practice recruiting only 8% of eligible children was an outlier, and due in part to recruitment at this practice commencing late into the study and therefore fewer clinics (in relation to the practice size) were set up compared with other practices.