hemoglobin-oxygen affinity; pO2 for 50% hemoglobin saturation with oxygen; oxygen P50

Partial pressure of oxygen when hemoglobin is 50% saturated. Normal range: - Adult: 25-29 mm Hg - Newborn: 18-24 mm Hg Increases: increases with decreased affinity of hemoglobin for O₂ 1) shift of hemoglobin dissociation curve to right 2) hyperthermia 3) acidemia 4) hypercapnia 5) increases in 2,3-DPG 6) abnormal hemoglobin - hemoglobin Seattle Decreases: decreases with increased affinity of hemoglobin for O₂ 1) shift of hemoglobin dissociation curve to left 2) hypothermia 3) acute alkalemia 4) hypocapnia 5) decreased 2,3-DPG 6) preeclampsia 7) abnormal hemoglobin a) hemoglobin Yakima b) hemoglobin F Specimen: - whole blood (heparin) Method: - determined by spectrophotometry

References

Clinical Guide to Laboratory Tests, 3rd edition, NW Tietz ed, WB Saunders, Philadelphia, 1995