RADIOMETER ABL800 FLEX Reference Manual

5. Performance characteristics ABL800 FLEX Reference Manual
Interference tests, Continued
FHbF sensitivity
for pH changes
FHbF is sensitive to pH deviations from the nominal value of pH = 7.4. If pH is
converted into
cH
+
(hydrogen ion concentration), the relationship between the
changes in
cH
+
and FHbF is linear as seen from the following equation:
∆FHbF = −0.48 %/(nmol/L) × (cH
+
− 40 nmol/L)
where pH = 7.4 corresponds to
cH
+
= 40 nmol/L.
EXAMPLE: pH = 7.25 corresponds to cH
+
= 56 nmol/L. Then:
∆FHbF = −0.48 × (56 − 40) = −7.7 %.
MCHC (Mean Corpuscular Hemoglobin Concentration) is used to estimate
hematocrit, Hct, which is used in the
ctBil measurement. MCHC is an average Hb
concentration in the red blood cell (RBC). If the RBC volume decreases, MCHC
increases. If a RBC has iron deficit, MCHC decreases.
ctBil sensitivity
for MCHC
variations
Hct is determined from ctHb as follows:
Hct
tHb
MCHC
=
c
A standard value of 332 g/L is assumed for MCHC which gives
Hct = ctHb x 0.0301 if the unit for ctHb is g/dL.
MCHC can, however, deviate from this standard value as illustrated in the
following table (see the next page).
Erythrocytometric values given for “apparently healthy” white and black subjects
of different ages are taken from: “Geigy Scientific Tables, Physical Chemistry,
Composition of Blood, Hematology, Somametric Data”, CIBA-GEIGY, 1984; 3,
207.
Continued on next page
5-52

RADIOMETER ABL800 FLEX Specifications

General

Brand	RADIOMETER
Model	ABL800 FLEX
Category	Measuring Instruments
Language	English