Laboratory results for ESR and RBC indices (hemoglobin, MCV, MCH, RDW… etc) should be extracted from the Laboratory databases. For Mayo, from January 1994 till October 2009, ESR and RBC test results were populated for our 3336 participants. All samples were collected on an outpatient basis. Samples collected during an inpatient hospitalization (admit date ≤ collection date ≤ discharge date) should be excluded unless this sample was the only one available for a patient. Since ESR levels and RBC indices can be affected by a variety of medical and therapeutic conditions, we implemented several strategies in order to detect and exclude samples that were taken at times of active disorders that may affect the variables being analyzed. We first followed a general set of exclusion rules for RBC indices analysis and then applied an additional set of rules for ESR pool of samples.
