ITC IRMA TruPoint Blood Analysis System - Manual (Page 147)

C.3
CALCULATED PARAMETERS
Other parameters can be calculated by the IRMA TruPoint analyzer based on
the measured values of a blood sample. See Appendix B, Table B- 8 for the
list of calculated parameters reported by the IRMA TruPoint system. The
following equations are used to calculate each of the parameters:
Bicarbonate 3,11
Two formulas are available for the calculation of bicarbonate: Severinghaus/
NCCLS or Siggaard-Andersen. Refer to Section 7-Calculations for instruc-
tions on formula selection.
Severinghaus/NCCLS formula is based on the Henderson Hasselbach
equation:
[HCO
3
-] = 0.0307 x pCO
2
x 10 (pH-6.1)
Siggaard-Andersen formula:
[HCO
3
-] = 0.230 x pCO
2
x antilg (pH-pKp)
› pKp = 6.125-lg{1 + antilg(pH-8.7)}
Total Carbon Dioxide 3,11
Total carbon dioxide, [TCO
2
], is the sum of bicarbonate and dissolved CO
2
.
TCO
2
= [H
2
CO
3
] + [HCO
3
-]
Severinghaus/NCCLS Bicarbonate formula:
[H
2
CO
3
] = 0.0307 x pCO
2
or
TCO
2
= 0.0307 x pCO
2
+ [HCO
3
-]
Siggaard-Andersen Bicarbonate formula:
[H
2
CO
3
] = 0.230 x pCO
2
or
TCO
2
= 0.230 x pCO
2
+ [HCO
3
-]