Recommendation on sampling, transport, and storage for the determination of the concentration of ionized calcium in whole blood, plasma, and serum. IFC Scientific Division, Working Group on Ion-Selective Electrodes (WGSE).
J Int Fed Clin Chem
; 4(4): 147-52, 1992 Sep.
Article
en En
| MEDLINE
| ID: mdl-10148305
ABSTRACT
The substance concentration of ionized calcium (cCa 2+) in blood, plasma, or serum preanalytically may be affected by pH changes of the sample, calcium binding by heparin, and dilution by the anticoagulant solution. pH changes in whole blood can be minimized by anaerobic sampling to avoid loss of CO 2, by measuring as soon as possible, or by storing the sample in iced water to avoid lactic acid formation. cCa 2+ and pH should be determined simultaneously. Plasma or serum If centrifuged in a closed tube and measured immediately, the pH of the sample will be close to the original value. If there has been a delay between centrifugation and measurement, causing substantial loss of CO 2, equilibration of the sample with a gas mixture corresponding to pCO 2 = 5.3 kPa prior to the measurement is recommended. Conversion of the measured values to cCa 2+ (7.4) is only valid if the pH is in the range 7.2-7.6. Ca 2+ binding by heparin can be minimized by using either of the following 1) a final concentration of sodium or lithium heparinate of 15 IU/mL blood or less; or 2) calcium-titrated heparin with a final concentration of less than 50 IU/mL blood. Dilution effect can be avoided by use of dry heparin in capillaries or syringes.(ABSTRACT TRUNCATED AT 250 WORDS)
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Plasma
/
Análisis Químico de la Sangre
/
Recolección de Muestras de Sangre
/
Calcio
Tipo de estudio:
Guideline
Límite:
Humans
Idioma:
En
Revista:
J Int Fed Clin Chem
Asunto de la revista:
QUIMICA CLINICA
Año:
1992
Tipo del documento:
Article