Specifications
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RBC Red Blood Cells (Erythrocytes)
The red blood cell dilution contains all the cellular elements of the blood, RBC,
WBC and PLT. During the counting platelets, are not counted since the size falls
below the threshold (discriminator). Leukocytes however, are always included in
the RBC count. Since the concentration ratio between RBC and WBC is normally
ca. 1000, the introduced error is almost negligible.
In case of high WBC counts with low RBC, the RBC count may be corrected by
simply subtracting the WBC from RBC.
Agglutinated red blood cells
This might cause a falsely decreased RBC count. Blood samples containing the
agglutinated red blood cells may be identified by observing abnormal MCH and
MCHC values as well as by examination of the stained blood film.
Cold agglutinins
IgM immunoglobulins which are elevated in cold agglutinin disease may lower
RBC and PLT counts and increase the MCV.
HGB (hemoglobin)
Turbidity of the blood sample due to any number of physiological and/or thera-
peutic factors may produce falsely elevated HGB results. The CA620/530 how-
ever is compensated for this effect with high WBC counts up to WBC approx. 60
10e3/µl. In case of extreme WBC counts, the following is recommended:
1. Elevated WBC
The diluted sample should be centrifuged and the supernatant fluid checked
on a spectrophotometer for turbidity.
2. Elevated lipids
Elevated lipids in the blood sample will give the plasma a “milky” appear-
ance. This condition can occur with hyperlipidemia, hyperproteinemia and
hypobilirubinemia. Accurate HGB determination can be achieved by using
reference methods and a plasma blank.
Increased turbidity may also be seen in cases where the red blood cells are resis-
tant to lyzing. This condition will cause a falsely elevated HGB result but can be
detected by monitoring the MCHC.
Fetal blood
The mixing of fetal and maternal bloods may produce a falsely elevated HGB val-
ue.
HCT (Hematocrit)
As HCT is the product of MCV x RBC, any erroneous result in MCV and/or
RBC will produce an equal error in the HCT parameter.
Red blood cell agglutination
May produce an erroneous MCV value and therefore a false HCT
WBC
An excessive number of WBCs might cause interference within the RBC popula-
tion and therefore a false MCV value.
PLT
Excessive numbers of PLT, in most cases, do not interfere with the MCV param-
eter due to the use of the floating discriminator technology in the instrument.
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