The NIH Pediatric Allergy Clinic has provided residents in the NIAID Allergy and Immunology Clinical Fellowship Program with medical training and continuity clinic experience in pediatric allergic diseases including asthma, allergic rhinitis, food allergy, atopic dermatitis and urticaria. During the past fiscal year, patient care visits exceeded 350, with a total accrual of 260 new patients. The NIH Pediatric Allergy Clinic also provides clinical resources for the study of children with allergic inflammatory disorders. In addition to standard diagnostic testing for allergic diseases, which includes skin prick testing, radioallergosorbent (RAST) testing, patch testing and pulmonary function testing, the clinic has integrated other modalities in the evaluation of children with allergic diseases. To evaluate lung function we have emplotyed impulse oscillometry, a non-invasive, non-effort dependant technique that measures lung resistance and elasticity. This is being used in conjunction with standard pulmonary function testing in older children and by itself in infants as young as two years old. A manuscript reviewing the clinical application of impulse oscillometry in pediatric patients with asthma is being prepared for publication. Through consultation with the NHLBI pulmonology service, exercise challenge pulmonary function testing has been performed. In conjunction with other investigators in the LAD, expired breath condensate and exhaled nitric oxide measurements have been obtained for diagnostic and research purposes. Research blood has been collected for laboratory studies to measure markers of allergic diseases, develop approaches to culture mast cells from blood, and determine cytokine and signaling profiles. In particular, serum tryptase levels were measured in 44 non-atopic and 153 atopic clinic patients. Median and 95% prediction intervals of tryptase levels for non-atopics were 3.44, 0.64-6.77 and 3.56, 0.98-10.80 for atopics. This study, recently published in the Journal of Allergy and Clinical Immunology (9 August 2009 on-line) establishes normative serum reference tryptase values in atopic and non-atopic children. Among atopics, a statistically significant association with tryptase was found for gender and race but not for ethnicity, total IgE levels, weight/weight percentile or eczema status. Patient documentation for communication with referring physicians and for longitudinal analysis is entered into CRIMSON, the NIAID database system.