Lecture 12 Flashcards
CBC Parameters – WBC count
WBC Differential
Relative DifferentiaL
Absolute Differential
WBC Differential -Differentiates’ the five types of White blood cells
Relative DifferentiaL-Ratio of each type of WBC - % or Fraction of 1.0
Absolute Differential -Total number of each type of WBC reported in x10^9 /L
CBC Parameters – RBC count
Hemoglobin (HGB)
Hematocrit (HCT)
RBC Count -Total Number of RBC reported in x1012/L
Hemoglobin (HGB)-The total grams Hemoglobin in one liter of blood (g/L)
Hematocrit (HCT)-The total volume of RBC (%) in the whole blood
Reported as the volume in L per L of whole blood (L/L)
RBC Indices
Mean Cell Volume
(MCV)
Mean Cell Hemoglobin (MCH)
Mean Cell Hemoglobin Concentration (MCHC)
RBC Distribution Width
(RDW)
Mean Cell Volume (MCV) -The average size or volume of an RBC (fL)
*AVERAGE of macro/micro
* Used to classify anemias
* RI 80-100 fL
‒ Normal MCV = Normocytic RBCs
‒ MCV > 100 = Macrocytic RBCs
‒ MCV < 80 = Microcytic RBCs
Mean Cell Hemoglobin
(MCH)- The average weight/mass or amount of Hemoglobin per RBC (pg)
*does not look at cell size must be done with MCV
=HGB/RBC
Mean Cell Hemoglobin Concentration (MCHC) -The average concentration of Hemoglobin per RBC (g/L)
*classify anemia
MCHC 320-360 g/L
*less than 320 hypochromic
*over 360- hyper or hereditary spherocytosis
*over 380 specimen integrity - lipemia, icterus, high WBC , lysing
=HGB/HCT
RBC Distribution Width
(RDW) -The variation in size of all of the RBCs (expressed as %)
-11.5 – 14.5%
CBC Parameters – PLT count
Mean Platelet Volume (MPV)
Platelet Distribution Width
(PDW
Mean Platelet Volume (MPV) -Average size of platelets (fL)
Platelet Distribution Width
(PDW)-Variation in size of platelets (expressed as %)
Reference Interval (RI)
-results seen in the majority of healthy people
- Specific RI given according to (where there is a difference):
‒ Sex
‒ Age
CBC Review & Interpretation
● All parameters within Action Limits – no smear needed
‒ Parameters may be outside RI, however, they are not significantly
abnormal
‒ CBC reported
● Any parameters outside Action Limits – make a smear
‒ Significantly abnormal
‒ CBC not reported
What will be PBF manual count if in automated
RBC - HIGH
WBC - HIGH
PLATELET - HIGH
RBC - cells close together - less white space in tail
WBC = increased WBC cytosis
PLT - increased PLT
What will be PBF manual count if in automated
RBC -low
WBC - low
PLATELET - low
RBC - Smear runs long less RBC more plasma
Excess white space showing
between cells
WBC = decreased WBC estimate - penia
PLT - decreased PLT estimate
What will be PBF manual count if in automated **
MCV -HIGH
MCV - LOW
MPV - HIGH
RDW - HIGH
MCV -Large RBC - Macrocytes
MCV - Small RBC - Microcytes
MPV - Giant PLTs
RDW - Anisocytosis:
* Macro, Micro, or both
(or with Retics)
What will be PBF manual count if in automated
MCH / MCHC -low
MCHC - HIGH
MCH / MCHC -Hypochromic RBC
* RBC have less hemoglobin
‒ Increased Central Pallor
MCHC - * RBC can only hold so much HGB
‒ Spherocytes present
‒ Interfering substance present
CBC – HGB, MCH & MCHC are all ↓
Low HGB due to decreased or
abnormal production:
* RBCs show increased central pallor
(hypochromasia)
* Some shape changes due to
decreased internal cell volume
HGB is Low
&
RBC is Low
MCH & MCHC
are Normal
Each individual RBC has a normal amount of hemoglobin but
there are less RB
Three main reasons:
1. Error in BM production
2. Early destruction
3. Loss of blood
RBC Distribution Width (RDW)
● Presence and degree of Anisocytosis (variation in RBC size)
‒ Increases are important, decreases are not clinically significant
- ‘Normocytes’ & Microcytes MCV Decreased
- ‘Normocytes’ & Macrocytes MCV Increased
- Microcytes & Macrocytes MCV -Normal
- Microcytes & Reticulocytes MCV- Normal
MCV normal but RDW is high
Anisocytosis – Dual Populations
- When two distinct populations of RBCs are seen,-dual/dimorphic population
‒Typically, a normal population along with an abnormal population
▪ E.g., Normochromic /Normocytic and hypochromic/microcytic cell -in a
treated Iron Deficiency anemia patient - reported as Dual Population
Systematic Approach to CBC Interpretation RBC Parameters
Anemia is suspected (low HGB value), we interpret our CBC as follows:
Step 1- look as HGB concentration and HCT size to assess the anemia
Step 2 - Look at MCV to assess cell volume - relate it with RDW and RI - normo, micro and macro
Step 3- Look at MCHC to see how well the RBC are filled up aka the HGB concentration
-relate it with RI-Normo/Hypo
Hyper spherocytes present, cold agglutinins or lipemic/hemolyzed
Step 4 - Look at RDW to assess anisocytosis or size variation and relate with MCV
Step 5 - Look at PBF for RBC morph and relate to CBC values also look for a Retic response
Purpose of the WBC Differential
- Total WBC count per liter of whole blood
- Differential determines proportion of each type of WBC per liter of whole blood (auto or manual)
- Total WBC count is not always significant
‒ Normal WBC count could have abnormal Diff %
WBC Differential
automated vs manual
-‘slot’ cells into 5 mature WBC types vs Visual interpretation of cells using morphological criteria
-Will ‘flag’ if there are any cells which do not fit any one type’s criteria vs Can identify 5 mature WBC and most immature forms
- Will ‘guess’ at abnormal type vs Can detect morphological abnormalities
Counts 1000s of cells vs Counts 100 WBC
WBC Differential Reporting
Relative Differential
Absolute Differential
Relative Differential
The ratio (% or fraction of 1) for each WBC type
The relative percentage is converted to the total number of that specific leukocyte by multiplying the ratio to the total WBC count
Relative Neutrophil 0.50 ratio
‒ WBC count of 20.0 x 10^9 /L
Relative x WBC = 0.50 x 20.0 = 10.0
therefore 10.0 x 10^9/L
NEUTROPHILIA
NEUTROPENIA
LEFT SHIFT
NEUTROPHILIA-An increase in # of neutrophils
NEUTROPENIA -A decrease in # of neutrophils
LEFT SHIFT -increase in Band forms usually counted with segmented Neuts
LYMPHOCYTOSIS
LYMPHOPENIA
MONOCYTOSIS
EOSINOPHILIA
BASOPHILIA
Thrombocytosis
Thrombocytopenia
LYMPHOCYTOSIS -An increase in the # of lymphocytes
LYMPHOPENIA -A decrease in the # of lymphocytes
MONOCYTOSIS -An increase in the # of monocytes
EOSINOPHILIA -An increase in the # of eosinophils
BASOPHILIA -An increase in the # of basophils
Thrombocytosis increase in PLT
Thrombocytopenia decrease in PLT
Systematic Approach to CBC Interpretation WBC Parameters
Step 1- ensure the WBC count correct via histogram/scatterplot
Step 2 - compare total WBC with RI
Step 3/4 - look at relative and absolute counts . The sum of absolute and total WBC should match
Step 5 - note any premature cells and look at WBC histogram/scatterplot
Step 6 - Note morph abnormalities
Systematic Approach to CBC Interpretation PLT Parameters
Step 1- look at total plt count. normal? cytosis? penia?
Step 2 look at MPV to asses platelet volume for example high MPV corresponds with increase PLT
Step 3 - Look at Plt morph and match with numeric values
Arrangement - clumped/aggregated
size - giant thrombo
granularity - agranular or hypo granular
