defined as chronic cough or wheezing responsive to bronchodilator. Atopy was defined as a positive skin prick test and symptoms consistent with allergic rhinitis. Patients were on inhaled corticosteroids for asthma and nasal ste-roids for allergic rhinitis. They had to be able to perform spirometry and not be on oral steroids. METHODS. Observations were made in a 4-step sequence: (1) exhaled nitric oxide fraction (FeNO) measurement with a portable NIOX MINO (Aerocrine Inc, Morrisville, NC; #35 ppb 5 controlled, .35 ppb 5 uncontrolled); (2) spirometry (forced expiratory volume in 1 second $80%, forced expiratory flow, midexpiratory phase $60%, peak expiratory flow rate $80% and forced expiratory volume in 1 second/forced vital capacity $80% 5 controlled); (3) childhood Asthma Control Test (cACT) (,19 5 uncontrolled); and (4) clinical assessment by a pediatrician without knowledge of preceding results. RESULTS. A total of 71 children (mean age 8.4 years; 46 boys and 25 girls) completed the study. The mean FeNO is uncontrolled asthma and was 37 ppb vs 15 ppb in controlled asthma (P , .005) but with considerable overlap. Comparison of individual spirometric indices revealed some correlation, but of the unrelated comparisons, those that agreed with each other most often (69%) were clinical assessment by the pediatrician and the cACT. Worst agreement was noted for FeNO and cACT (49.3%). CONCLUSIONS. Overall this study revealed significant disagreement among many of the common methods used to assess asthma control. REVIEWER COMMENTS. Asthma control is the key to successful management, and assessment of control is recommended in all major guidelines. It is nice to have different measures to choose from but disheartening to see the lack of agreement between tests. Previous studies have also shown a lack of agreement between many of these measures. The authors speculate that taking the individual patient's asthma phenotype into consideration may be the key and that a combination of physician assessment and objective testing will be required. We continue to wait for the perfect test or combination of tests. PURPOSE OF THE STUDY. To address the question: How well does bronchial hyperresponsiveness (BHR) predict later clinical asthma? STUDY POPULATION. Five hundred thirty children in a prospective population-based birth cohort underwent a meth-acholine challenge and exercise challenge on separate days at age 10 years. At age 16 years, they underwent a clinical evaluation and repeat methacholine challenge. METHODS. BHR was scored as follows based the meth-acholine dose causing a 20% …