Admission and discharge diagnoses in hospitals are often in discord, and this has significant implications for the cost of care and patient safety. In this paper we used medical claims data to examine these differences for beneficiaries with respiratory conditions and quantified the degree to which specific respiratory conditions are mistaken for other ones, on admission. Since respiratory problems have seasonality, we performed two separate analyses, for summer and for winter admissions. The length of stay and hospital charges were compared between matching and non-matching {admission, discharge Dx} pairs, using independent samples t-test analysis. Results were integrated into a standalone application where physicians can select an admission diagnosis to see (i) the probability for this diagnosis to be correct (matching the discharge Dx), (ii) the probabilities for mismatch and (iii) pair-specific differential diagnosis criteria to consider reassessing the patient before confirming the admission diagnosis.