Medonic CA530, User Manual

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Specifications
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2.6 Limitations
Verification of any abnormal test result (including flagged results or results out-
side of the normal range) should be performed using reference methods or other
standard laboratory procedures for the conclusive verification of results. The sec-
tion below list known limitations of automated blood cell counters in general as
well as specific issues for cell counters using the impedance technology.
WBC White Blood Cells (Leukocytes)
WBC that exceeds the linearity limits of the system will require dilution of the
blood sample. Re-assaying the diluted sample will help to obtain the correct assay
value.
NRBC
Immature Nucleated Red Blood Cells will be counted in the WBC parameter. If
the number of the NRBC is sufficient to activate the DE alarm, such interference
will be detected. However, the manual differential blood cell count, performed
on a stained blood film, will reveal the presence of NRBCs.
Unlyzed Red Cells
In particularly rare instances, the RBC in the blood sample may not completely
lyze. These non-lyzed cells may be detected on the WBC histogram with a DE
alarm or as an elevated baseline on the side of the lymphocyte population. Non-
lyzed RBCs will cause a falsely elevated WBC count. (See also NRBC above)
Multiple myeloma
The precipitation of proteins in multiple myeloma patients may give elevated
WBC counts.
Hemolyzis
Hemolyzed specimen contains red cell stroma (debris), which may elevate the
WBC and/or PLT count.
Leukemias
This disease state may result in a spurious low WBC count because of the pos-
sible increased fragility of the leukocytes leading to some destruction of these
cells during counting. The cell fragments will also interfere with the white cell par-
tial differential parameters (LYMF, GRAN and MID). A spurious low WBC
count may also be seen in patients with lymphocytic leukemias due to the pres-
ence of abnormally small lymphocytes, which may not be counted by the instru-
ment.
Chemotherapy
Cytotoxic and immunosuppressive drugs may increase the fragility of the leuko-
cytes, which may cause low WBC counts.
Cryoglobulins
Increased levels of cryoglobin that may be associated with myeloma, carcinoma,
leukemias, macroglobulinemia, lymphoproliferative disorders, metastatic tu-
mours, auto immune disorders, infections, idiopathic disease, aneurism, pregnan-
cy, thromboembolic phenomena, diabetes etc. and may cause elevated levels of
WBC, RBC or PLT counts as well as HGB. The specimen can be warmed up to
37
°
C and re-analysed immediately or a manual WBC, RBC or PLT count can be
performed.