Clinical chemistry
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Case Reports
A novel hemoglobin, Bonn, causes falsely decreased oxygen saturation measurements in pulse oximetry.
A 4-year-old boy and his father exhibited low oxygen saturation measured transcutaneously by pulse oximetry, a finding that could not be confirmed by arterial blood gas analysis. Both patients exhibited slight hemolysis in their blood, and the boy had a microcytic anemia. There was no evidence of hypoxemia or methemoglobinemia. Despite the normal results from the arterial blood gas analysis, a right-to-left-shunt was assumed in the boy until a cardiology examination excluded this diagnosis. Sleep apnea syndrome was suspected in the father and treated with nocturnal positive pressure respiration based on the low oxygen saturation values obtained with pulse oximetry. Only after consultation with our laboratory was a hemoglobin variant suspected and investigated. ⋯ Hemoglobin Bonn is a novel hemoglobin variant of the proximal alpha-globin that results in falsely low oxygen saturation measurements with pulse oximetry.
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Choline is critical for a variety of biological functions and has been investigated as a biomarker for various pathological conditions including acute coronary syndrome. ⋯ Sample collection, storage, and sample preparation procedures are critical for clinical measurements of choline in whole blood and plasma.