1. Automated CBC Parameters Quality Control
and
Quality Control
Joanna Ellis, MLS(ASCP)

2. The Automated Complete Blood Count
Most common test in the Hematology lab.
Main Components of the CBC:
Cell counts
Hgb
RBC indices
WBC differential absolute values and percent
Indications for CBC:
Fatigue
Weakness
Infection
Inflammation
Bruising
Bleeding
The CBC is a very common test. Many patients will have baseline CBC tests to help determine their general health status. If they are healthy and they have cell populations that are within normal limits, then they may not require another CBC until their health status changes or until their doctor feels that it is necessary.
If a patient is having symptoms such as fatigue or weakness or has an infection, inflammation, bruising, or bleeding, then the doctor may order a CBC to help diagnose the cause.

3. COMMON METHOD OF DETERMINATION
CBC Parameters
PARAMETER
UNIT OF REPORTING
COMMON METHOD OF DETERMINATION
WBC
X 103 /µL
Impedance count X calibration (cal) factor
RBC
X 106 /µL
Impedance count X calibration factor
HGB
g/dL
Colorimetric absorbance in proportion to hemoglobin
MCV fL
From RBC histogram,
#of RBCs X size of RBCs X cal constant OR Calculated: HCT X 10
HCT %
Calculated: RBC X MCV 10
MCH Pg
Calculated: HGB X 10
MCHC
g/dL or %
Calculated: HGB X 100
RDW
Impedance (from histogram)
Platelet
Impedance count X cal factor
WBC Diff
Absolute: X103 /µL
Percent of WBC : %
Light Scatter , flow cytometry
We have discussed the principles of impedance, colorimetric determinations, light scatter, and flow cytometry in the previous powerpoints. This chart simplifies the parameter, the units of reporting, and the most commonly used method of determination.

4. M77221

5. CBC Adult Reference Ranges
Parameter
Adult Reference Range
WBC
X 103/µL
RBC
Male: X 106 /µL
Female: X 106 /µL
HGB
Male: g/dL
Female: g/dL
HCT
Male: %
Female: %
MCV fl
MCH
28-34 pg
MCHC
32-36 g/dL or %
RDW %
PLT
X 103 /µL
MPV fl
This chart can also be found in on the first page of the textbook.

6. Linearity (Reportable Range)
Instruments are calibrated for each analyte with a range that is clinically relevant.
With concentrations above or below the reportable range or Linearity range, the result does not correspond with the calibration curve in linear fashion.
Results outside of linearity are NOT acceptable.
Linearity ranges vary by instrument.
Example:
The instrument will be accurate as long as the results fall within a certain range known as the linearity range also known as the reportable range. When patient results are higher or lower than the reportable range, the results do not match up the standard curve or calibration curve in a straight line; therefore, they cannot be standardized. The results cannot be reported. Some instruments FLAG these results, others give values of greater than the highest reportable value. Many times the specimen will need to be diluted, rerun and the result multiplied by the dilution factor to get a result within linearity.
Parameter
Coulter STKS
Advia
WBC
X 103 /µL
X 103 /µL

7. Advia Linearity Instrument Codes
Cause
Action Indicated
+++++
Result exceeds reportable range
Dilute 1:2 and rerun.
Continue further dilutions until result is within linearity H
Result higher than the laboratory set patient high action limit
Review Result L
Result is lower than the laboratory set patient low action limit
These codes are on the CBC results sheet when a certain parameter is beyond set limits. There are abnormal results that generate flags or abnormal codes. We will be discuss the document “Handling Abnormal Results” next.

8. CBC Quality Control Commercial Controls: 3 levels (low, normal, high)
Values stored in instrument computer
Levey-Jennings graph generated and stored for each parameter
Mode to Mode QC:
Most automated hematology instruments have a primary and secondary mode of sample aspiration. Controls must be run on BOTH and correlate.
Primary=Automated or Closed
Secondary=Manual or Open
Delta Checks
When the Laboratory Information System (LIS) and the instrument are interfaced (connected) delta checks are conducted by the LIS on select parameters.
Current values compared to most previous result
Differences greater than the limits set within the LIS are flagged

9. WBC Parameter Interfering substances and Implications
Test
Name
Interfering Agent
Clinical Implications
WBC
White Blood Cell Count
Unusual RBC abnormalities that resist lysis
Nucleated RBCs
Fragmented WBCs
Unlysed particles greater than 35 fL
Very large or aggregated plts
Specimens containing fibrin, cell fragments or other debris (esp pediatric/oncology specimens
LOW <4.5 X103 /µL
some medications (such as methotrexate),
some autoimmune conditions
some severe infections
bone marrow failure
HIGH: >11.0 X103 /µL
Infections
Inflammation
cancer, leukemia

10. RBC Parameter Interfering substances and Implications
Test
Name
Interfering Agent
Clinical Implications
RBC
Red
Blood Cell Count
Very high WBC count (greater than 99.9)
High concentration of very large platelets
Agglutinated RBCs, rouleaux will break up when Istoton is added
RBCs smaller than 36 fL
Specimens containing fibrin, cell fragments or other debris (esp pediatric/oncology specimens
LOW:
Male: < 4.5 X 106 /µL
Female: < 4.0 X 106 /µL
Anemia
HIGH:
Male: > 5.5 X 106 /µL
Female: > 5.0 X 106 /µL
Polycythemia vera,
fluid loss due to diarrhea, dehydration, buns

11. HGB Parameter Interfering substances and Implications
Test
Name
Interfering Agent
Clinical Implications
HGB Or Hb
Hemoglobin
Very high WBC count
Severe lipemia
Heparin
Certain unusual RBC abnormalities that resist lysing
Anything that increases the turbidity of the sample such as elevated levels of triglycerides
High bilirubin
LOW:
Male: <14 g/dL
Female: <12.0 g/dL
Anemia
HIGH:
Male: > 17.4 g/dL
Female: >16.0 g/dL
Polycythemia vera
fluid loss due to diarrhea, dehydration, burns

12. HCT Parameter Interfering substances and Implications
Test
Name
Interfering Agent
Clinical Implications
HCT
Hematocrit
Known factors that interfere with the parameters used for computation, RBC and MCV
LOW:
Male: <42%
Female: <36%
Anemia
HIGH:
Male: >52%
Female: <46%
Polycythemia vera
fluid loss due to diarrhea, dehydration, burns

13. MCV Parameter Interfering substances and Implications
Test
Name
Interfering Agent
Clinical Implications
MCV
Mean
Corpuscular (Cell) Volume
Very high WBC count
High concentration of very large platelets
Agglutinated RBCs
RBC fragments that fall below the 36 fL threshold
Rigid RBCs
LOW: <80 fL
Iron deficiency anemia
Thalassemia
HIGH: >100 fL
B12
Folate Deficiency

14. RDW Parameter Interfering substances and Implications
Test
Name
Interfering Agent
Clinical Implications
RDW
Red Cell Distribution Width
Very high WBC
High concentration of very large or clumped platelets
RBCs below the 36 fL threshold
Two distinct populations of RBCs
RBC agglutinates
Rigid RBCs
HIGH: >14.6%
Mixed population of RBCs
Immature RBCs tend to be larger

15. Plt Parameter Interfering substances and Implications
Test
Name
Interfering Agent
Clinical Implications
Plt
Platelet Count
Very small red cells near the upper threshold
Cell fragments
Clumped platelets
Cellular debris near the lower platelet threshold
LOW: < 150 X 103 /µL
Bleeding
Wiskott-Aldrich,
Bernard-Soulier
Systemic lupus erythematosus
Pernicious anemia
Hypersplenism (spleen takes too many out of circulation)
Leukemia
Chemotherapy
HIGH: >450 X 103 /µL
Benign idiopathic thrombocytosis
Myeloproliferative disorders
Polycythemia vera

16. WBC Differential Parameters Clinical Implications in Adults
Test
Name
Clinical Implications of LOW %
Clinical Implications of HIGH %
Neut %
Neutrophil %
In 100 WBC
differential
LOW: <40%
Chemotherapy
Severe infection
HIGH: >80%
Bacterial infection
Inflammatory disease
Chronic myelogenous leukemia
Lymph %
Lymphocyte %
LOW: <25%
Lupus
Later stages of HIV infection.
HIGH: >35%
Viral infection
Chronic or Acute Lymphocytic Leukemia
Mono %
Monocyte %
LOW: <2%
Bone Marrow Insufficiency
HIGH: >10%
Inflammatory disorders
Myelomonocytic leukemia
Eos %
Eosinophil %
HIGH: >5%
Parasitic infection
Allergic reaction
Baso %
Basophil %
HIGH: >1%
Allergic reaction to food
Chronic inflammation

17. References
Harmening., Denise, Clinical Hematology and Fundamentals of Hemostasis, 3rd edition, pp
Turgeon, Mary Louise, Clinical Hematology - Theories and Procedures, 3rd edition, pp373,
Rodak, Bernadette, Diagnostic Hematology, 1st edition, p
Coulter STKS Operating Manual
McKenzie, Shirlyn, Clinical Laboratory Hematology, 2nd edition,pp
"Complete Blood Count: The Test." Lab Tests Online: Welcome! American Association for Clinical Chemistry, 18 June Web. 13 Sept < /test.html#how>.
"WBC Differential Count: The Test." Lab Tests Online: Welcome! American Association for Clinical Chemistry, 18 June Web. 13 Sept ferential/test.html#what>.