complete blood count CBC Flashcards
provides information about the number and types of cells in the body
CBC
components of CBC
- White blood cells (WBC)
- Red blood cells (RBC)
- Hemoglobin, hematocrit, red cell indices
- Platelets
critical WBC
Critical < 2000 and > 40,000
bone marrow failure, viral infection, aplastic anemia, vitamin
deficiencies, B12 or iron deficiences, autoimmune diseases, drug toxicity
Decreased (leukopenia)
inflammation, infection, leukemia, malignancies, vascular conditions,
tissue necrosis, steroids, stress from trauma, seizures/uncontrolled shivering, thyroid storm,
dehydration
Elevated (leukocytosis)
First responders to bacterial infections, commonly elevated in bacterial infections, trauma,
or stress
neutrophils
% of each type of leukocyte present
differential count
specific WBCs including granulocytes (neutrophils, eosinophils, basophils) and nongranulocytes (lymphocytes, monocytes)
differential
Elevated in allergies, asthma, and parasitic infections
eosinophils
Involved in inflammatory responses, rarely elevated but can be seen in chronic myelogenous
leukemia (CML)
basophils
Elevated in viral infections, chronic inflammation, or certain cancers (e.g., lymphocytic leukemia)
lymphocytes
Engulf pathogens, increased in chronic infections, tuberculosis, and certain leukemias
monocytes
mature, have a segmented nucleus
Segmented neutrophils
- Most common type
- Produced in 7-14 days, only live for 6 hours
- Function = phagocytosis (pacman)
- Neutrophilia = elevated, inflammation (RA, thyroiditis), Cushing syndrome
- Neutropenia = decreased, drugs, chemo/radiation, anaplastic anemia, viral infections
(measles, hepatitis, influenza) - Leukocytosis + Neutrophilia = SEPTIC BILLS
o Severe bacterial infection, Exercise, Postsplenectomy, Trauma, Inflammation, Corticosteroids, Burns,
Infarction, Leukemia, Loss of blood, Surgery/smoking
neutrophils
- Indicates a patient’s real risk of infection
- Calculated by:
- ANC = WBC x (% neutrophils + bands)
- Normal value: 2500 – 8000
- < 1,000 indicates immunosuppression
- Patient should be isolated as he/she is at a high risk for infection
Absolute Neutrophil Count (ANC)
less mature, have a unsegmented nucleus shaped like a C
or S
band neutrophils
elevated in allergies ranging from seasonal allergies to allergic reactions
o Carry enzymes and proteins that are released to destroy what the body flags as harmful
o Eosinophilia = too many eosinophils, can cause inflammation leading to swelling, itching, rashes, wheezing
o Specific conditions like eosinophilic esophagitis = chronic allergic condition that causes inflammation of
esophagus
eosinophils
increase in immature cells (stab cells, band neutrophils =
bandemia)
o When the bone marrow is stimulated to release neutrophils at a rate faster than it can
produce them, it releases them at increasingly more immature stages
o Bacterial infection, inflammation, tissue damage
o Large = severe infection, the infection is depleting the first responders quicker than the
body can release them
o Labs will show an elevated neutrophil band count
left shift
helps fight against allergens, parasites, and pathogens
o Largest granulocyte, but least common
o Allergic reactions = basophils release histamine during allergic reactions to improve blood flow to
damaged tissue
o Asthma = Basophils release enzymes during asthma attacks
o Blood clotting = Basophils release heparin to prevent blood clots
* They do not change due to bacterial or viral infections
basophils
- Produced in bone marrow
- Divided into T cells and B cells
- T cells
- Cellular-type reactions
- Killer cells, suppressor, and T4 helper cells
- B cells
- Antibody production to attack bacteria, viruses, and toxins
- Cellular memory: Lymphocytes recognize pathogens they’ve been exposed to before and
reproduce to fight them off - Seen in chronic bacterial and acute viral infections
lymphocytes
- Similar to neutrophils with phagocytosis
- Largest WBC
- Last longer in circulation
- Search and destroy pathogens and infected cells
- During an inflammatory response they produce cytokines to help control infection
- Help engulf dead or damaged cells and help facilitate regeneration of injured tissue
monocytes
Direct count of RBCs
Used to assess overall RBC production and size
* Normal 3.9-5.5 x 106/μL
* Decreased = all types of anemias
* Increased = may be erroneously high with elevated WBCs, polycythemia vera, OSA
RBCs
- Normal male 40-54%, female 36-48%
- Percentage of red blood cells in a venous blood sample
- 45% = 45% cells, 55% plasma
- Hemodilution = fluid overloaded with crystalloids = low Hct
Hemoglobin (Hgb) - Normal males 13.8-17.2 g/dL and females 12.1-15.1 g/dL
- Protein that carries oxygen to the cells and CO2 back to lungs
- Elevated = hemoconcentration = dehydration, burns, vomiting
- Decreased = anemia
H/H
Hematocrit (Hct)
The average size of red blood cells
Mean Corpuscular Volume (MCV)
The average amount of hemoglobin per red blood
cell
Mean Corpuscular Hemoglobin (MCH)
The concentration of hemoglobin
in a given volume of red blood cells
Mean Corpuscular Hemoglobin Concentration (MCHC):
Measures the variation in the size of red blood cells.
Red Cell Distribution Width (RDW)
A high RDW may indicate
mixed types of anemia
A low MCV indicates
microcytic anemia
high MCV suggests
macrocytic anemia
Essential for blood clotting and wound healing
* Normal 150,000–450,000/μL
platelets
myeloproliferative disorders
Elevated platelets (thrombocytosis)
bleeding risk, DIC (disseminated intravascular coagulation),
high level of platelet antibodies
Decreased platelets (thrombocytopenia)
informing the size and function of the platelet
MPV = mean platelet volume,
how is a CBC performed
o Typically performed using an automated hematology analyzer
o In cases where the automated results are unclear, a manual count may be performed, often by a
laboratory technician under a microscope
Limitations of CBC testing
o It’s important to note that while CBCs are very accurate, there are some limitations
o Certain conditions, such as dehydration or fluid overload, can artificially affect the results
Eating, physical activity, stress (acute phase reactions)
Pregnancy/labor, splenectomy, drawing time: morning vs. evening, age-related
Drugs
* Increase = adrenaline, Allopurinol, Aspirin, Heparin, steroids
* Decrease = antibiotics, anticonvulsants, antihistamines, antithyroid meds, chemo
when to order a CBC
- It helps diagnose, monitor, and assess
o It is a screening tool and can not be used in isolation for diagnosis - A patient presenting with fatigue, pallor, and shortness of breath
- A febrile patient with chills or signs of sepsis
- A patient with unexplained bruising, prolonged bleeding
- General screening for routine physical exam or preop evaluation
- When general symptoms present, currently non-specific symptoms, to narrow differential dx
interpreting CBC results
o RBC, Hgb, or Hct low
o MCV to classify type of anemia (microcytic, normocytic, macrocytic)
anemia
interpreting CBC results
bleeding risk vs. myeloproliferative disorder
Thrombocytosis/thrombocytopenia
interpreting CBC results
infection/inflammation vs. Bone marrow dysfunction
Leukocytosis/leukopenia
universal recipients
AB
universal donors
type O
protein on RBC that determines whether positive or negative
Rh factor
human leukocyte antigen = protein on surface of cells that help body
determine self from alien
HLA
determine blood type and Rh factor, crossmatch by mixing donor blood with sample of patient’s to ensure no negative reactions such as clumping of blood cells
type and crossmatch
contains all blood components, degrades quickly
whole blood
retain characteristics of whole blood except 250 mL of platelet-rich plasma
packed red blood cells
RBC or platelet products
washed blood products
WBCs and platelet fragments filtered out
Leuko-reduced blood products
exposed to radiation
Irradiated blood products
- Blood components developed in bone marrow
- Consist of cytoplasmic fragments that contain enzymes necessary for normal clotting response
platelets
Uncoagulated plasma separated from RBCs; used for blood loss, coagulation deficiencies, warfarin
reversal
fresh frozen plasma
- Frozen blood product created from donor’s plasma; used for hemophilia A, fibrinogen deficiency
cryoprecipitate
- Fractionation of pooled plasma
albumin
- Contains 83% albumin, 17% globulins
Plasma protein fraction
- Hemopure
Synthetic blood substitutes
can occur during phlebotomy, processing, and thawing
bacterial contamination
indications for a transfusion process
significant blood loss, symptomatic anemia, dropping Hgb or Hct levels,
decreased clotting factors
caused by allergens in donated blood, treat with antihistamines
allergic reactions
bacterial lipopolysaccharides or antileukocyte recipient
antibodies, treat with antipyretics and antihistamines
febrile transfusion reaction
immediate or delayed, caused by incompatibility or error
hemolytic transfusion reactions
immunoglobulin A incompatibility
plasma protein incompatibility
