exam 4- cbc Flashcards
When to order a CBC
– Screening for anemia
– Suspect hematological disorder
– Toxic child
– Caution: well visit, well child with negative history
• Road to CBC Hell
• Well child with mild viral illness has transient abnormalities
How 1To Approach the CBC
evaluate RBC line
evaluate WBC line
Evaluate platelets
Look at smear (cell morph)
Normocytic RBC
rbc size is normal but not enough of them (anemia)
Microcytic
RBC size is smaller than normal
Macrocytic
RBC size is larger than normal
MCV
Mean corpsucle volume
avg volume of red cells
RDW
Red cell distribution width
Coefficient of ariation of RBC volume distribution
3 important questions for red cell line
1) is child anemic
2) what kind of anemia does pt have? micro/normo/macro
3) if it is microscopic anemia, do one of the following indices
Mentzer Index
RBC/MCV:
> 13: iron def.
Rule of 3s
Measured Hgb calc should be 3x RBC
calculated HCT is 3x HgB
Eleven Plus 1 point rule
11= 00.1 x (age in year) is lower limit of normal (3rd percentile) for hgb
normocytic
RBC size normal but not enough of them
Microcytic
RBC size is smaller than normal
macrocytic
RBC size is larger than normal
seventy plus 1 rule
70 + 1 x age years is lower limit of normal for MCV
What values help you determine anemia?
– RDW (Red Blood cell distribution width)
– MCV (Mean corpuscle volume)
• What is low of normal?
• LLNL (MCV) = Age (yrs + 70)
– Only use once child is 2 years and up to 10
• After 10 values for adolescent are the
same.
RDW
• Red Cell Distribution Width (RDW)
Coefficient of variation of the red cell volume
histagram distribution, i. e how much does the red
cell vary
– Very helpful in diagnosis of microcytosis
– RDW Normals
• In thalassemia minor may be 1 or 2 points over the
upper normal
• However in iron deficiency, frequently very elevated
ranging from 14-25
Causes of Microcytic anemia
• Most Common: – Iron Deficiency and Thalassemia • Less Common: – Hemoglobin C disease, Hemoglobin D disease, anemia of inflammation – Hereditary pyropoikilocytosis (Lead Poisoning Rare – SideroblasCc anemia – Copper deficiency – Pyridoxine deficiency
Causes of Iron Deficiency- dec absorption
Achlorhydria (producCon of gastric acid in the stomach is absent or low) Celiac disease Competing metal Fe deficiency Clay starch
increased losses
GI GU Lung (pulm emosiderosis) joints facticious pregnancy lbood donation newborn exchange iatrogenic
physio anemia in infancy
• Term Infant: Anemia in the first 2 to 3 months of life – physiologic anemia of infancy – not due to iron deficiency – Does not respond to iron therapy. • Preterm infants – appears at 1 to 2 months of age and is oten more severe.
Normochromic anemias
Normochromic – Hereditary Spherocytosis – Hereditary Elliptocytosis – G6PD deficiency – Aplas)c anemia – Acute blood loss
Macrocytic
– Vitamin B12 deficiency
– Folate deficiency
– Liver disease
– Lots of re)culocytes (due to hemolysis)
Hemolytic Anemia
Sickle Cell disease
SC disease
Sickle Cell anemia
Sickle Thalassemia
White Cell line
• Suspected hematological disorder
• Evaluation of systemic disease or infection
• There is poor sensivity and specificity in
differenciating bacterial from viral infection
Factors that Interfere with the Normal
WBC
AGE – High neutrophil count during the first several days of life • RACE – African Americans have lower WBC • MINOR ILLNESS – Widely variable leukocyte count – Neutropenia is not uncommon during a viral illness • MEASUREMENT METHOD – Inherent error
Neutrophils fx
• First line of defense against bacterial infection – Major function: • Phagocytosis • Killing of microorganisms –Enzymatic degradation • At birth, decrease rapidly after birth within first few days • Infancy 20-30% of circulating WBC • At age 5 years, equal neutrophil and lymphocytes • At puberty reaches 70% predominance found in adult. • Most abundant type of WBC • Also known as Polymorphic Nuclear Leukocyte • Can see granules when stained • Band is the immature Neutrophil – Is an acute phase response
Neutropenia
• Add the neutrophils and Bands together and multiply by the total WBC count • What is neutrophil count if WBC is 4,500 with 2 Bands, and 10 neutrophils? 4,500 X .12 540 is the ANC
Classification of Neutropenia
In African Americans, 30% may have 1000 as normal • Caucasian 8000 to 1500 normal • Mild neutropenia: 1500-1000 • Moderate neutropenia: 1000-500 • Severe neutropenia:
Increased Neutrophils
– Physiologic – newborn, stress exercise
– Acute hemorrhage
– Acute bacterial infecCon
– Metabolic derangement—diabetes, acidosis, anoxia, burn,
seizures
– Drugs-epinephrine, steroids, lithium
– ConnecCve Cssue disease-JIA, Inflammatory Bowel disease
– Hematological disorders—Cancers, hemolysis splenectomy
WBC Eval
• Shit to the let is an increase in the number of
immature neutrophils—bands and metamyelocyte -
>5% bands
• Absolute lymphocytosis
– Physiologic 2 months to 4 year
– Increased in pertussis, TB, mononucleosis, CMV, measles,
adenovirus, syphilis
– Leukemia
• Lymphopenia
Lymphocytes:
Small mononuclear cells • Coordinate/execute immune response via release of inflammatory cytokines • Bone marrow/Thymus are primary lymphoid organs • Secondary organ is spleen
Lymphocytosis
greater than 5000) • Response to acute viral infections • Chronic infections states such as TB, Syphilis • Also seen in ALL, Non Hodgkin's Lymphoma
Monocytes
1- 10 % of Leukocytes
• Large cells with blue-gray cytoplasm
• Reniform (kidney) shaped (i.e. folded nuclei)
• Efficient at digesCon of fungi and
microbacteria
• Return of Monocytes precedes return of
neutrophils by 1-2 days
Basophils
Less than 1% of Leukocytes
Contain large cytoplasmic granules and sulfated
acidic proteins
• Express IgE receptors
• Release Histamine when stimulated
• Above 150u/L= Basophilia which is associated
with hypersensitivity reactuions
Basophilia is associated w viral infections such as
varicella
flu
TB
Eosinophils
Bilobed nucleus with a red granulocyte filled cytoplasm • Fight parasites • Control Allergic Reactions • Eosinophilia usually seen when Eosinophils make up more than 10% of WBC’s • Hypereosinophilia persisting for months can cause tissue damage
WBC Evaluation: Eosinophilia
500 cells per mm2
• N – Neoplasm
– Hodgkin’s lymphoma (HL) is commonly associated with eosinophilia.
– Can also occur with carcinomas,
– Can be related to the breakdown of tumor cells
– Neoplastic cells have shown to produce factors that increase eosinophil producCon.
• A - Addison’s disease
– Decreased cortisol levels lead to eosinophilia, because normally cortisol sequesters
eosinophils back into the lymph nodes.
• A - Allergy/asthma
– asthma, allergic rhinitis, and drug reacCons. (remember eosinophilic esophagiCs, too)
• C - Collagen vascular (autoimmune) disease
– Eosinophilia can be associated with rheumatoid arthritis, polyarteriCs nodosa, and ChurgStrauss
syndrome, among others.
• P- Parasites -Typically associated with parasites that invade tissues, like T. canis and
helminthes (worms).
Platelet line
• Life span is 8-9 days • One third are sequestered in the spleen • Normal count 150,000 to 450,000 • Pseudothrombocytopenia – ArCficially low count due to clumping – EDTA-dependent anCbody against platelets – Suspect if the low platelet count and paCent is well – Clumps of platelets on a blood film from EDTA specimen
platelet and bleeding categories
> 100,000
– No bleeding
50,000 to 100,000
– Small amount of
bleeding may offer
ater trauma
20,000 to 50,000
• Mild cutaneous
bleeding
5,000 to 20,000
• Moderate cutaneous
and mucosal bleeding
Thrombocytosis
• ACUTE PHASE REACTANT
• DefiniCon: platelet count >450,000/mm3
• Causes:
– InfecCon, collagen disease malignancy, stress, post
operaCve, iron deficiency, following marrow recovery
or splenectomy or in myeloproliferaCve disease (rare)
• Manage by treaCng the underlying disease and/
or benign neglect unless over 1 million
repeatedly
RBC shapes
• Red blood cells – Poikilocytosis (difference in shapes) – Anisocytosis (difference in size) – Hypochromia (pale cells) – Microcytosis (small cells) – membranopathies (spherocytosis, ovalocytosis, elliptocytosis) – Basophillic sCppling (aggregated ribosomal DNA and mitochondrial fragments) seen in lead poisoning and thalassemia • Red Blood Cells – Spherocytes • ArCfactual, immune mediated hemolyCc anemia, spherocytosis – Nucleated erythrocytes-hemolyCc disease – Schistocytes and helmet cells (microangiopathic hemolyCc anemia – Speculated erythrocytes and acanthoctyes (spur cells) in pyruvate kinase deficiency – Bite or blister cells in Glucose-6- phosphate deficiency – Target cells in iron deficiency, liver disease hemoglobinopathies, postsplenoectomy – Howell jolly bodies splenic hypofuncCon
WBCs
• White blood cells
– Atypical lymphocytes (predominately an acCvated T
lymphocytes responding to the B-cell infecCon)
– Metamyelocyte
– Blasts
– Dohle Bodies are bluish cytoplasmic inclusions in
neutrophils in bacterial infecCon, burns,
myelodysplasia, pregnancy
– Chediak Higashi syndrome: giant azurophilic granules
in lymphocytes
ThALASSEMIA
• Prevalent in America – estimates of 2 million carriers in US
• Likely related to protective effect of thalassemia traits on
malarial disease
• Hemoglobinopathy – dysfunction of the synthesis of
hemoglobin
– Thalassemias -deficit in the production of one of the hemoglobin
chains
• Iron Deficiency Anemia and Thalassemia Trait are the most
common causes of microcytic anemia in Peds.
Hemoglobin Production
• Four globin chains • In utero fetal hemoglobin (HbF) – Two alpha globin chains – Two gamma globin chains • Hemoglobin A (HbA) – Two alpha chains – Two beta chains • Hemoglobin A2 – Two alpha chains – Two delta chains
Normocytic Anemia
• Blood loss
• Decreased production of red blood cells
– Marrow failure
• Increased destruction of red blood cells
– Hemolytic Anemia
Distinguished by reculocyte count
Decreased in states of decreased production
Increased in destruction of red blood cells
Reticulocyte count- reasons to order
• Reasons for ordering this test
– Normocytic anemia
– Acute blood loss ( usually doubling of reticulocyte
count in first 24 hours)
– Problems with bone marrow
– Response to anemia therapy
– Infections
• Parvovirus causes aplasia of bone marrow since there
is no new RBC production for 7 days
– Drugs causing hemolysis or bone marrow aplasia
Reticulocyte Production Index
• Corrected reticulocyte count
• Raw reticulocyte count: misleading in anemic
patients.
– Reticulocyte count is a percentage
• Number of reticulocytes as a percentage of the number
of red blood cells.
• In anemia, the patient’s red blood cells are
depleted, creating an erroneously elevated
reticulocyte count.
• Corrects the reticulocyte count for the
degree of anemia
– evaluates whether the bone marrow’s
response is appropriate.
• ReCculocyte producCon should increase in
response to any loss of red blood cells
• Increase within 2–3 days of a hemorrhage
• Will peak in 6–10
RPI=
RPI = reticulocyte count X the patient’s
hemoglobin/ normal hemoglobin X .5
• Or Reticulocyte Index = Hematocrit/normal Hematocrit
• RPI >3: increased production of reticulocytes
suggesting either hemolysis or blood loss
• RPI
Lab signs of Hemolysis
Increased lactate dehydrogenase (LDH) • Increased unconjugated bilirubin • Decreased serum haptoglobin • RBC indices demonstrate an increase in MCHC.
Urine dipstick
– PH – Blood – Protein – Leukocytes – Nitrites – Urobilogen – Specific gravity
Urine Dipstick pH
Alkaline specimen is indicaCve of urinary tract infecCon but in late
aternoon, may have higher pH and be normal
• Normal range is 4.5-8.5
• Alkaline (>7.0)
– Bacteriuria
– renal failure
– presence of anCbioCcs, sodium bicarbonate
– diet high in vegetables, citrus fruits and dairy products
• Acidic (
Urine dipstick-blood
Extremely sensitve and so will detect clinically
insignificantly amounts of hemoglobin or
myoglobin
• Mild
• Moderate
• Severe
Urine Dipstick nitrate and leukocyte Esterase
Negative nitrite result
– does not rule out UTI (poor sensitivity)
• Positive result is likely true-positive
– high specificity—whatever the collection method.
• Leukocyte esterase
– More sensitive (positive in disease) indicator of
infection than nitrites are
– Better when tested using a catheterized, rather
than a bagged, specimen.
• Negative nitrite result
– does not rule out UTI (poor sensitivity)
• Positive result is likely true-positive
– high specificity—whatever the collection method.
• Leukocyte esterase
– More sensitive (positive in disease) indicator of
infection than nitrites are
– Better when tested using a catheterized, rather
than a bagged, specimen.
Urine dipstick glucose/bili
• Urine should not contain glucose
• False posiCve can occur with ascorbic acid
• Most common reason for posiCve bilirubin is
old or poorly sealed dipsCck
urine dipstick-protein amounts
• trace (about 15 mg/dL) • 1+ (about 30 mg/dL) • 2+ (about 100 mg/dL) • 3+ (about 300 mg/dL) • 4+ (2,000 mg/dL or greater). • Urine dipstick measures albumin – Does not measure low molecular weight protein
dipstick interp.
• Urinary dipstick method measures the concentration of urine protein, – false-negative resultsvery dilute urine specimen. • If the urine sample has specific gravity of ≤ to 1.015, then 1+ is considered positive • If the urine sample has a specific gravity of ≥ to 1.015 then >/= to 2+ is positive • False-positive results – Very alkaline or concentrated specimens – Gross hematuria – Pyuria – Bacteriuria – Presence of contaminating antiseptics – Radiographic contrast – Presence of heavy mucus, blood, pus, semen or vaginal secretion • Trace positive proteinuria by dipstick does not imply pathologic proteinuria
quantitative urine tests
• Urine protein/creatinine ratio – Random urine specimen – More accurate quantification – Normal ratio is .03 mg of albumin per milligram of albumin is abnormal
Asymptomatic microscopic Hematuria
• In a study of 20,000 school aged children, 274
had a negative history and normal exam
• 0 had UTI
• 57 had hypercalcuria
• 3 had recent episode of poststreptococcal
glomerulonephritis
