Limitations Of The Procedure; Xpected Alues - Siemens ADVIA 2120 Operator's Manual

Limitations of the Procedure

The limitations of the procedure are as listed:
1. Some irreversibly sickled cells that occur in cases of sickle cell anemia may
not completely sphere in the system, resulting in an elevated RDW and
therefore an underestimation of the MCV. Sickled cells may cause erroneous
results in other RBC parameters.
2. Very high WBC counts (>200 x 10³ cells/µL) elevate the red blood cell
count.
3. Samples with cold agglutinins may falsely lower the red blood cell count.
4. Samples with high WBC counts (>60 x 10³ cells/µL), or platelet clumps, and
neonatal samples may interfere with the hemoglobin determination.
5. Samples with extreme lipemia, chylomicrons, or extremely high bilirubin
might interfere with and elevate the hemoglobin results obtained from the
hemoglobin method, including the MCHC.
Since these interferences do not affect the cell-by-cell hemoglobin
concentration values obtained from the RBC method, the CHCM values are
unaffected. If the MCHC and CHCM differ by more than 1.9 g/dL, a
"Comparison Error" system flag alerts the operator to this condition.
6. Patient specimens with nucleated RBCs (particularly neonate specimens)
may falsely elevate the WBC count. When manually correcting the WBC
count for the presence of NRBCs, use the WBCB count.
7. Samples from patients receiving total parenteral nutrition (TPN) including
high lipid dosage may exhibit falsely elevated platelet counts. These samples
can include lipid droplets that appear in the platelet counting region, thus
elevating the platelet count.
Expected Values
The range of expected values can vary depending on age, sex, diet, and location.
It is recommended that each laboratory establish its own range of expected
values.
The following range of expected values is based upon the duplicate assay of 60
whole-blood specimens obtained from an adult population of assumed healthy
individuals.
Parameter
WBC (10³/µL)
RBC (10
HGB (g/dL)
HCT (%)
Regulatory Information
Low Value High Value
3.8
6
/µL) 4.1
10
33
8.6
6.0
16
57
9-29