Distribution and Suspected Causes of Methemoglobinemia at an Academic Medical Center

Supplementary file 1: Data for methemoglobin concentrations in whole blood specimens performed at the University of Iowa Hospitals and Clinics from May 1, 2009 to June 22, 2023. The data elements for the “All Values” tab (which contains all methemoglobin values in the above timeframe) include: deidentified patient number, legal sex in the electronic medical record, patient age in years at time of methemoglobin measurement (greater than 89 years expressed as ">89"), location type (outpatient or inpatient) for where methemoglobin measurement was made, quantitative methemoglobin value (%), methemoglobin category (0.0-3.0%, 3.1-4.9%, 5.0-9.9%, and 10+%), and pediatric/adult at time of testing (pediatric defined as < 18 years old). The data elements for the “Episodes with MetHb >=3.1%” field (which contains only those episodes of care with a methemoglobin concentrations of 3.1% or higher) include: deidentified patient number, legal sex in the electronic medical record, patient age in years at time of methemoglobin measurement (greater than 89 years expressed as ">89"), location type (outpatient or inpatient) for where methemoglobin measurement was made, methemoglobin cause category from chart review, highest quantitative methemoglobin value (%) during episode of care, methemoglobin category (0.0-3.0%, 3.1-4.9%, 5.0-9.9%, and 10+%), pediatric/adult (pediatric defined as < 18 years old), asymptomatic during episode (yes/no), cardiovascular symptoms during episode (yes/no), cough during episode (yes/no), cyanosis during episode (yes/no), death during episode of care (yes/no), dizziness and/or loss of balance during episode (yes/no), edema during episode (yes/no), fatigue during episode (yes/no), gastrointestinal pain during episode (yes/no), nausea/vomiting during episode (yes/no), respiratory difficulties during episode (yes/no).

Supplementary file 2: Data for methemoglobin concentrations in whole blood specimens performed at the University of Iowa Hospitals and Clinics from January 1, 1996 to April 30, 2009. The data elements for the “All Values” tab (which contains all methemoglobin values in the above timeframe) are the same as the “All Values” tab in Supplemental file 1. The data elements for the “Episodes with MetHb >=10.0%” field contain only those episodes of care with a methemoglobin concentrations of 10.0% or higher. Data elements are the same as those in the “Episodes with MetHb >=3.1%” tab in Supplemental file 1.