External Quality Assessment (EQA) in medical laboratories have evolved over the past 50 years to provide more sophisticated systems compared with the simple participants’ analytical performance evaluation of earlier years.  There are clear distinctions between the proficiency testing schemes and the evolved External...

p50 is a shorthand representation of hemoglobin-oxygen affinity. A lower p50 is protective in ambient hypoxemia, whereas increasing the p50 should be beneficial in hypoxia due to lung disease, anemia, and tissue ischemia. Despite encouraging theoretical and experimental data, it is not yet established that...