CBC and Urinalysis Flashcards
When to order CBC (3)
- Screening for anemia
- Suspected hematological disorder
- Toxic child
RBC size (3)
- Normocytic –> RBC size is normal but there is not enough of them (anemia)
- Microcytic –> RBC size is smaller than normal
- Macrocytic –> RBC size is larger than normal
Microcytic, Hypochromic (3)
- Many RBCs smaller than nucleus of normal lymphocytes, increased central pallor
- Occurs with iron deficiency, thalassemias, anemia of chronic disease.
- The red cells tend to be very small and have central pallor
MCV: Mean Corpuscle Volume (6)
- Helps you determine size of red cell
- Determining low of normal
- Age (years + 70)
- Only used between 2-10 years old
- So lower limit of normal is 70
- Upper limit of normal is 90 - Ex: If child is 2, lower limit is 72
- If child is 10, lower limit of normal is 80
RDW: Red Cell Distribution Width (4)
- Coefficient of variation of the red cell volume distribution
- How much do the red cells look like each other?
- When RDW is elevated, cells don’t look like each other
- When RDW is low or normal, ells look like each other
Mentzer Index (3)
- Determined by MCV/RBC
- Value greater than 13 suggests iron deficiency
- Less than 13 it suggests thalassemia.
Calculating Hct from Hgb
Hct = 3 x Hgb
MCH vs. MCHC
- MCH: Amount of HgB/RBC
- MCHC: Portion of RBC occupied by HgB
- CHR =Retic - He
Red Cell Line Shape vs. Size
Shape = RDW
Size = MCV
RBC Rule of 3’s
- Hemoglobin is 3x RBC
- Hematocrit is 3x Hgb
- The lower limit of normal for the hemoglobin is 11 + (0.1 x age in years)
Seventy Plus One Rule
70 + (age in years) is the lower limit of normal for MCV
RDW Levels (3)
- Normal: 11-14
- Thalassemia: slightly over upper limit by 1-2 points or normal
- Iron deficiency anemia: 14-25 (very elevated)
CHr (Advia) Or Retic-He (Sysmex) (4)
- This value measure the amounts of hemoglobin in reticulocyte
- Normal value is > 28 picogram (pg)
- This is a measure of iron available for producing new RBC’s
- Value is reduced in iron deficiency and thalassemia
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: Sideroblastic anemia, Copper deficiency, Pyridoxine deficiency
Causes of Iron Deficiency Anemia: Decreased Absorption (6)
- Achlorhydria (production of gastric acid in the stomach is absent or low)
- Celiac disease
- Competing metal
- Iron deficiency
- Clay
- Starch
Causes of Iron Deficiency Anemia: Increased Loss (9)
BLEEDING
- GI
- GU (menses, hemosidinuria)
- Lung (pulmonary hemosiderosis)
- Joints (hemarthroses)
- Factitious
- Pregnancy
- Frequent blood donation
- Newborn exchange transfusion
- Iatrogenic
Differential Dx of Normocytic Anemia
- Blood Loss
- Decreased RBC Production
- Ex: bone marrow isn’t working adequately - Increased RBC Destruction
Physiological Anemia of Term Infant (3)
- Anemia in the first 2-3 months of life
- Not due to iron deficiency
- Does not respond to iron therapy
Physiological Anemia of Pre-Term Infant
Appears at 1-2 months of age and is often more severe
Normochromic Anemias (5)
- Hereditary Spherocytosis
- Hereditary Elliptocytosis
- G6PD deficiency
- Aplastic anemia
- Acute blood loss
Macrocytic Anemias (4)
a. Vitamin B12 deficiency
b. Folate deficiency
c. Liver Disease
d. Loss of reticulocytes (due to hemolysis)
Anemia Lab Values: Electrophoresis (5)
- Iron deficiency anemia: normal
- Thalassemia: increased HbA2 or F
- Chronic inflammation: normal
- Lead poisoning: normal
- Sickle Disease: HbSS
Anemia Lab Values: ESR (5)
- Iron deficiency anemia: normal
- Thalassemia: normal
- Chronic inflammation: increased
- Lead poisoning: normal
- Sickle Disease: low
Anemia Lab Values: Smear (5)
- Iron deficiency anemia: hypochromic, target cells
- Thalassemia: normocrhomic, microcytic
- Chronic inflammation: varies
- Lead poisoning: basophilic stippling
- Sickle Disease: sickle cell
Factors that Interfere with Normal WBC (4)
- Age- High neutrophil count during 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 errrors
Neutrophils (8)
- First line of defense against bacterial infection
- Major function are phagocytosis and killing microorganisms via enzymatic degredation
- High in first few days of life, Decrease rapidly after birth within first few days
- On the lower side in infancy (20-30% of circulating WBC) - At age 5 years old, equal neutrophils and lymphocytes
- At puberty, reaches 70% predominance found in adult
- Most abundant type of WBC
- Can see granules when stained
- Band is the immature neutrophil; Is an acute phase response; goes up with severe infection