Lab Med CBC Flashcards
Components of automated CBC
- Total WBC count – White Blood Cell (leukocyte)
- Differential means automated (i.e. via machine, not manual)
- RBC count – Red Blood Cell (erythrocyte)
- H&H – Hemoglobin and Hematocrit
- RBC indices (MCV, MCH, MCHC, RDW)
- Plt count - Platelet
- Plt indices
What do you NOT get in automated CBC?
- the reticulocyte count
- band count and immature cell count- must specify on order (order manual differential)
What is the function of lymphocytes?
assist in building immunity and include B and T cells
Total WBC Breakdown on Differential
- LYMPHS – Lymphocytes
- MONOS – Monocytes
- Granulocytes = Neutrophils, Eosinophils, & Basophils
- POLYS – Neutrophils (segs)
- EOS – Eosinophils
- BA – Basophils
Define Agranulocytosis
- (aka: Bone Marrow Failure) is the deficiency of granulocytes
- pt is more susceptible to infections
If suspicious of blood dyscrasias you should…
Specify manual differential on order.
Total WBC count
Provides a count of all 5 types of WBCs:
Neutrophils, Basophils, Eosinophils, Monocytes, and Lymphocytes
Normal range for total WBC count
~ 4 – 11,000/mm3
Neonatal Leukocytosis
- Birth – 3 days = 18 – 22 K
- 3 – 4 days = 8 – 16 K
- Adult levels at 6 months – in reference to neutrophils
- During neonatal period (<1 month) segs predominate (~60%)
- From 1 month to 4 years lymphs predominate (60%)
- After 4 y/o returns to adult pattern (60% segs, 40% lymphs)
What is the most numerous WBC?
Neutrophil (polymorphocyte) poly
Neutrophil (polymorphocyte) poly characteristics
- Multi-lobed nucleus (2-5 lobes) and a pale cytoplasm with an irregular outline and fine azurophilic granules
- Has 6-10 hour lifespan
What is the primary cause of Neutrophilic leukocytosis?
-bacterial infection
Neutrophilic leukocytosis characteristics
Usually accompanied by increased band count (left shift)
Bandemia
Increased band (immature neutrophil) count
No elevation in neutrophils may be seen with:
- Overwhelming infection (Sepsis)
- Debilitated patients (Cancer, Autoimmune D/O)
- Elderly and Infancy
- ECHO viral infections are common (enteric colitis) in US most of the time asymptomatic, but more serious in infants, elderly and immune compromised
Non-infectious causes of Neutrophilic Leukocytosis
- Tissue destruction: burns, abscess, trauma, MI, CA, cirrhosis
- Metabolic toxic states: uremia, DKA, gout, last trimester of pregnancy
- Drugs: corticosteroids, lithium, epi, albuterol
- Others: lead poisoning, leukemia, demargination = extravasation – into surrounding tissue due to innate immune response. (sepsis)
Leukopenia (AKA Neutropenia)
Decline in WBC count
Neutropenia is primarily associated with…
- overwhelming infection/septicemia,
- hypersplenism (SLE, Mononucleosis -EBV),
- drugs/anemias/leukemias
- d/t bone marrow suppression or destruction
Monocytosis is most associated with
-Subacute bacterial endocarditis
-Consider leukemia
-Also, collagen diseases, sarcoidosis, ulcerative collitis, sprue
(Elevated monocyte count)
Eosinophilia
- Most commonly seen in roundworm infections d/t peroxidases, neurotoxins in granuoles
- Asthma and allergic rhinitis (clear nose drop)
- Chronic skin diseases, e.g., psoriasis, eczema
- EOS have limited bacterial phagocytic ability
Basophilia
- Most common cause is chronic myelogenous leukemia
- Also parasitic infections
- Activated in inflammatory/hypersensitivity rxn
- Histamine/hep/SRS-A cause vasodilation, capillary leakage, bronchoconstriction, serve as chemoattractants
Right shift vs. left shift
Right shift = increase in the percentage of lymphocytes
Left shift = increase in band count
Lymphocytosis
- Most common cause is viral infection
- NL to decreased WBC count d/t decrease in segs; however, relative since total lymph numbers remain constant
- Real lymphocytosis d/t pertussis, mono (atypical), lymphocytic leukemia, adenovirus
The RBC count measures…
- circulating RBCs
- indirect measure of hemoglobin (Hgb) – Due to RBC being carrier for Hgb
Reticulocyte is increased in…
-Hemolytic anemia
–Acute/chronic bleed
–After treatment with B12/folate/iron
Hgb - Hemoglobin
Carried by the RBC – binds to O2 and Fe for transport
Hgb males vs. females
Anemia <13 gms/dl (males), <12 gms/dl (females) d/t body habitus & volume
HCT – Hematocrit
- Ratio of Volume of RBCs to the total volume of blood
- Another, indirect measure of Hgb
- Roughly 3x the Hgb value
- Each 1 unit of red cells (packed or whole) = Hgb 1 gm/dl and the HCT 3%
Calculating HCT
RBC count X MCV = HCT
Red Blood Cell count X Mean Corpuscular Volume is equal to Hematocrit
RBC Indices
- MCV – Mean Corpuscular Volume (size) = MICRO/NORMO/MACRO-cytic
- MCH – Mean Corpuscular Hemaglobin (mass/wt)
- MCHC – Mean Corpuscular Hemoglobin Concentration
–All 3 MCV, MCH and MCHC are used to further differentiate a type of anemia
Divide HGB by HCT
Determines amount of HGB to volume of cells
Plts – Platelets
(aka Thrombocyte)
Major clotting blood cell
Causes for increase in Plt count
~25% of increase d/t malignancy
- Polycythemia vera
- Splenectomy
Pancytopenia
Decrease of WBC, RBC and Plt counts
Etiology of pancytopenia
- toxins
- drugs
- infection
- myelodysplasia
- malignancy
- radiation
- vitamin B12/folate deficiency
- SLE (systemic lupus erythematosus
- congenital causes
Initial Anemia Lab Orders (4)
CBC
MCV
Blood Smear –(aka) peripheral smear
Reticulocyte Count
What is a peripheral smear?
- ID of every cell type present (looking for anything that is not common or normally present)
- ID of Cell stage within the hemopoiesis cell line (certain cell stages are present in greater number with certain diseases/blood dyscrasias)
Secondary Anemia Labs (5)
- Iron Lab Studies
- Hemoglobin electrophoresis – definitive diagnosis to confirm suspicion of thalassemia
- Hemolysis lab studies
- DIC Panel
- Bone Marrow Studies
Iron Lab Studies (9)
- Serum Iron level
- TIBC – total Iron binding capacity
- % saturation
- Ferritin level
- Serum folate
- Serum B12
- TSH – thyroid stimulating hormone
- Soluble transferrin receptor
- Serum Erythropoietin
Hemolysis
RBC is unable to maintain its intact structure
–> passage through circulation and reticuloendothelial system
Hemolysis Lab Studies (4)
- LDH- lactase dehydrogenase
- Unconjugated Bilirubin- picks up hemolysis disease if haptoglobin is not decreased
- Haptoglobin- decreased with hemolytic anemia
- Coombs’ Test
Positive Coombs test
- Indicative of Ab presence on the RBC
- Causing an immune response hemolysis of RBCs and rejection reaction
Negative Coombs test
- Indicative of no Ab presence on the RBC
- Hemolysis cause is from inherited or congenital blood dyscrasia
DIC panel
- D-dimer – fibrin degradation product (elevated)
- Plasma Fibrinogen (decrease)
- Platelet Count (decrease)
- PT (increase)
- PTT (increase)
- Blood smear
- Soluble fibrin monomer complex (increased with ongoing fibrinolysis)
Bone Marrow Aspirate/Biopsy
Aspirate is fluid (slide smear) vs. Biopsy is tissue (frozen section slides)
M/E Ratio (Myeloid/nucleated Erythroid cells) in bone marrow
- Normal adult varies from 1.2:1 to 5:1
- An increased M/E ratio (6:1) may be seen in infection, CML, or erythroid hyperplasia – increase in the reproduction rate of cells.
