Eval of Anemia

Question 1

Anemia

Answer 1

Anemia is a symptom NOT a disease, syndrome, or specific diagnosis

It is a decrease in blood red cell mass or hemoglobin which results in a decreased oxygen-carrying capacity

Anemia is a laboratory measurement indicating the red cell mass measurement (Hgb or Hct) in a patient is:
less than than ** 2.5 percentile value of reference range

Question 2

symptoms in severe anemia

Answer 2

fainting
chest pain
angina
heart attack

in addition to all the other ones for just mild anemia, SOB, pale, fatigue, dizzy, palpitations, enlarged spleen, etc.

Question 3

Three reasons to be anemic:

Answer 3

Blood loss
Increased destruction (hemolysis)
Decreased RBC production

Question 4

MCV is

Answer 4

measure of average red cell size

Question 5

Three Categories of MCV:

Answer 5

Microcytic = Decreased MCV
Low 60 –80 fL
Markedly low - under 60 fL

Normocytic = Normal MCV 80-100 fL

Macrocytic = High MCV > 100 fL

Question 6

MCHC

Answer 6

Mean cell hemoglobin concentration

MCHC is relevant value for “chromaticity” (Hgb concentration)

Question 7

MCHC “Chromaticity” in Anemia - RBC Hgb Concentration as an Adjunct to RBC Size

Answer 7

“Chromic” designations are coupled with size as a second important quantitative measure of individual red cells in anemia.
“Chromic” is listed before red cell size when using RBC indices to characterize the red cells present in an anemia. For example, iron deficiency anemia is a: Hypochromic Microcytic Anemia ***
“Normochromic” less frequently used; usually used in context of “Normochromic Normocytic” anemia, indicating red cells have normal amounts of hemoglobin and are of normal size… seen in hemolytic anemia
“Chromic” designation not used for macrocytic; MCHC values are invariably low because relative hemoglobin production is not increased at a rate greater than the red cell increases in size.

Question 8

Reticulocyte

Answer 8

Immature erythrocytes contain remnant endoplasmic reticulum & ribosomes (Rough ER) that forms a reticulum (net) within RBC cytoplasm
This remnant Ribosomal RNA reticulum stains blue with Methylene Blue ***

Reticulocytes represent ~2% of the red cell population
**

Reticulocytes are 20-30% larger than mature red blood cells and circulate for 2-3 days before all remnants of the ribosomal-endoplasmic structures are extruded.

Question 9

more about Reticulocytes:

Answer 9

Reticulocytes: These are young red cells released from the bone marrow into the peripheral circulation that have residual ribosomal RNA. This ribosomal RNA is extruded during the first 24 to 36 hours of circulation

This residual RNA allows detection and measurement of reticulocytes as a distinct population. Reticulocyte levels as a percentage of the peripheral red cell population provide a measure of the ** rate of production and release of red cells by the marrow into the peripheral blood. **

Question 10

Reticulocyte Count

Answer 10

adult reference range - 0.5 -1.5%

pediatric reference range – 3.0-7.0%

Question 11

Reticulocytosis

Answer 11

Reticulocyte production should increase in response to any loss of red blood cells; e.g., release of reticulocytes from marrow into peripheral blood should increase (reticulocytosis) 3-4 days ** after an episode of acute hemorrhage. The degree of reticulocytosis (reticulocyte count) should peak in 6-10 days.**

Question 12

Reticulocyte Index

Answer 12

Reticulocyte Count X Patient Hematocrit / 45% (normal Hct)

Question 13

Common Causes of Reticulocytosis

Answer 13

Acute blood loss or hemorrhage

Acute hemolysis

Hemolytic anemia

Response to therapy (Fe or other
nutritional correction of deficiency)

Question 14

Microcytic

Answer 14

MCV under 80

Question 15

Common Causes

Microcytic Anemia

Answer 15

Iron Deficiency
Iron Deficiency Anemia Anemia of Chronic Disease

Impairment Globin Synthesis
Alpha Thalassemia Beta Thalassemia

Decreased/Abnormal Synthesis Protopoporphyrin-Heme
Lead Intoxication anemia Sideroblastic anemia
Abnormal Hemoglobin
Hemoglobin C Disease

Question 16

Laboratory Approach to Diagnosis of Hypochromic, Microcytic

Answer 16

Serum Fe (50-170μg/dL)
Total Iron Binding Capacity (TIBC) (250-400μg/dL)
Soluble Transferrin Receptor (sTfR) (2-5mg/L)
Ferritin (20-250ng/mL)

Hemoglobin electrophoresis
- Hemoglobinopathies: thalassemias, hgb S, C

Lead level

Prussian blue Fe stain for ring sideroblasts in marrow

Question 17

Common Causes

Normocytic Anemia

Answer 17

Acute Blood Loss
Autoimmune Hemolytic
Anemia of Chronic Disease
     * Infection
     * Inflammation
     * Malignancy	

Anemia of Chronic Renal Failure

Bone Marrow Failure
* Aplastic Anemia
* Marrow Replacement
fibrosis/malignancy

Sickle Cell Anemia

Question 18

Normocytic reticulocyte count

Answer 18

.5-1.5%

Question 19

tests for hemolytic anemias

Answer 19

reticulocytes- tests changes in hematopoiesis (high)

coombs test- tests IgG coating RBCs (positive)

Hapotoglobin- free hemoglobin binding protein (low)

Hemoglobin electrophoresis - presence of abnormal hgbs (Hgb A2 and F- thalassemia, HgbS- sickle cell)

Bilirubin- RBC destruction (elevated)

RDW- variation in size of RBC pops - anisocytosis (high)

Peripheral smear (morphology)- fragmented RBCs, spherocytes, elliptocytes, nRBCs, dacrocytes

Question 20

Causes of macrocytic (megaloblastic) anemia

Answer 20

VItamin B12 deficiency

• decreased intake
• impaired absorption

Folic acid deficiency
- decreased intake
- impaired absorption
- increased loss
i- increased requirement (pregnancy)
- impaired utilization

Question 21

Laboratory Approach to Diagnosis- Macrocytic (Megaloblastic)

Answer 21

Reticulocytes
Peripheral smear
B12/Folate level