Drucker Diagnostics Paralens Advance - Manual (Page 60)

A-2.2 TEST LIMITATIONS
Quality medical care requires that laboratory values
be correlated with each patient’s symptoms and
signs by a trained practitioner.
Section A-2.1.2 lists the validated upper and lower
limits of the operating range. Values above and
below these validated ranges should be confirmed
by an alternate method.
Test values cannot be derived by the Autoread Plus
analyzer unless distinct cell layers with well-defined
interfaces form in the blood tube. Non-separation or
cell “streaming” can occur under certain hematologic
or pathologic conditions, e.g., when an orange-
yellow layer of granulocytes fails to form in the QBC
tube, or when the lower boundary of granulocytes
is so poorly defined that the instrument cannot
detect a clear interface. The condition is generally
the result of a shift in red-cell specific gravity toward
that of the granulocytic leukocytes, causing the red
cells and granulocytes to intermingle.
Studies indicate that the frequency of unreadable
QBC tubes among ambulatory office patients of the
general practitioner should average less than 1%.
Among clinical out-patients and hospital patients,
the frequency of unreadable tubes may range from
1.5% to 10%, depending on the pathologies of the
patient group.
9
User errors in processing or use of outdated
or inappropriately stored tubes can also result
in non-reported results. Practitioners must not
assume that unreported values are normal; further
testing with an alternative method is essential.
Automated granulocyte and lymphocyte/monocyte
differential counts cannot replace the conventional
manual differential. Due to grouping by density of
the cell populations by the QBC system method, the
system cannot discriminate between normal and
abnormal cell types in disease states characterized
by the presence of abnormal white cell types
or nucleated red blood cells. If abnormal cell
populations are suspected, verification of QBC
test results or testing and diagnosis by alternative
methods is essential.
The combined lymphocyte/monocyte count
should not be used to test for lymphocytopenia in
evaluating patients with known or possible immuno-
deficiencies. Further evaluation of lymphocyte/
monocyte counts in relevant situations must include
a manual differential and lymphocyte subset analysis.
A-2.3 EXPECTED VALUES
The following table provides normal ranges reported in
the literature.
1,12 Offices or laboratories may choose
to develop normal hematology ranges based on the
characteristics of their patient population.
Parameter Range
Hematocrit Males (%) 42-50
Hematocrit Females (%) 36-45
Hemoglobin Males (g/dL) 14-18
Hemoglobin Females (g/dL) 12-16
MCHC (g/dL) 31.7-36.0
Platelet Count (× 10 9 /L) 140-440
WBC (× 10 9 /L) 4.3-10.0
Granulocyte Count (× 10 9 /L) 1.8-7.2
Lymphocyte/Monocyte Count (× 10 9 /L) 1.7-4.9
A-2-2