User's Manual

i15 Blood Gas and Chemistry Analysis System User Manual Theory
- 120 -
11.2.2 Determination of Cell Concentration
Hct
In whole blood, the cellular constituents, red and white blood cells and platelets do not conduct
electricity, while plasma does. For a sample whose electrolyte concentration is given, the more
cells, the less conductivity. The total cell concentration of the whole blood is determined from:
1) The known value of the electrolyte concentration in the calibrant.
2) The measured electrolyte concentration of the sample.
3) The measured conductivity signal generated by the calibrant.
4) The measured conductivity signal generated by the sample.
CPB
When samples with abnormally low protein levels are tested, the system need to use the CPB
compensation algorithm. The CPB compensation algorithm is specially intended for use when
samples are taken from patients on cardiopulmonary bypass. It also applies to the adult whose
protein levels are abnormally low.
11.3 Equations for Calculated Parameters
cH
+
Hydrogen ion concentration
cH
+
= 10
(9 – pH)
[nmol/L]
HCO
3
-
act
Bicarbonate ion concentration
HCO
3
-
act = 0.0307 × pCO
2
× 10
(pH - 6.105)
[mmol/L]
HCO
3
-
std
Bicarbonate ion concentration normalized to a pCO
2
40mmHg
HCO
3
-
std = 24.5 + 0.9 × A + [(A - 2.9)
2
× (2.65 + 0.31 × tHb (est))] / 1000 [mmol/L]
Where A = BE (B) – [0.2 × tHb (est) × (100 - sO
2
(est))] / 100, tHb (est) can be entered by users,
and the default value for tHb (est) is 15g/dL.