J Lab Med Qual Assur.  2018 Mar;40(1):46-49. 10.15263/jlmqa.2018.40.1.46.

Usefulness of P(50,std) for the Diagnostic Work-up of Patients with Erythrocytosis

Affiliations
  • 1Department of Laboratory Medicine, Seoul Metropolitan Dongbu Hospital, Seoul, Korea. hypocra@naver.com

Abstract

High oxygen-affinity hemoglobin (Hb) variants and a 2,3-diphosphoglycerate (2,3-DPG) deficiency could cause congenital (familial) erythrocytosis. High oxygen-affinity Hb variants and a 2,3-DPG deficiency might result in low tissue oxygen tension left-shifted oxygen dissociation curves and reduction in the standard Pâ‚…â‚€ value (P(50,std), oxygen tension at which haemoglobin is 50% saturated). Hence, the P(50,std) value is considered while formulating diagnostic strategies for erythrocytosis. In this study, we established a reference range for P(50,std) using an International Federation of Clinical Chemistry and Laboratory Medicine-approved equation (Hill's equation) for individual single venous/arterial blood samples. Blood gas analysis results of 243 samples with oxygen saturation ranging from 40%-90% (Hb < 16 mg/dL) were selected. The reference range of P(50,std) was in the 2.5th-97.5th percentile, and was 25.9-27.3 mm Hg. Hill's equation is a simple approved method for evaluating the P(50,std) values. Only a single sample of venous or arterial blood and a blood gas analyser are required to obtain the P(50,std). Our study provides a useful tool for the diagnostic work-up of patients with erythrocytosis.

Keyword

Hill's equation; Pâ‚…â‚€; Polycythemia

MeSH Terms

2,3-Diphosphoglycerate
Blood Gas Analysis
Chemistry, Clinical
Humans
Methods
Oxygen
Polycythemia*
Reference Values
2,3-Diphosphoglycerate
Oxygen
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