RBC measurements:

-RBC mass (MCV), RBC count (MCH), H/H (MCHC), Morphology (RDW).

Polycythemia: increased RBC mass.

Anemia:decreased RBC mass; not a disease but a symptom.

-Most common symptom: Fatigue due to lack of oxygen for cell metabolism.

-Other symptoms:

-Pale skin, koilonychia (spooning of nails).

-Lab tests:

-CBC, RBC morphology, reticulocyte index (retic count), bilirubin.

-Relative hemoglobin:

-Measured in lab in g/dL; mass of Hb relative to plasma volume.

-Increased plasma volume (excessive hydration) can result in falsely low Hb.

-Loss of blood and plasma during acute hemorrhage may result in normal Hb; but Hb will be decreased later and plasma increased.

-Absolute hemoglobin:

-Total mass of Hb independent of plasma volume.

Serum iron:

-Iron metabolism:

-Fe is present in Hb and involved in oxygen transport.

-The rest are stored in bone marrow, spleen, liver, and myoglobin.

-Iron requirement increased during pregnancy, growth, and menstruation.

-Test: Enzyme immunoassay (EIA).

-Specimen:Draw in the morning due to diurnal variation; decreased iron in the afternoon.

-Reference range: varies with age, gender, and methodology.

Serum ferritin:

-Fe bound to apoferritin, forming ferritin (main storage form in body).

-Ferritin stores or releases iron for hematopoiesis (RBC production).

-Water soluble; Fe is readily available.

-Not stained by iron stain. Can be stained by Prussian blue stain.

-1st test value to decrease during iron deficiency anemia. Used to confirm iron deficiency.

-Acute phase protein; increased serum ferritin does not exclude iron deficiency anemia.

-Test: EIA

-Reference range: Varies with age, gender, and methodology.

Hemosiderin: Storage form of iron that is not readily available.

-Water-insoluble; contains 50% Fe.

-Can be stained by Prussian blue stain.

-Degradation product of ferritin.

Transferrin:

-Fe transport protein; carries iron to bone marrow for heme production.

-Free iron is toxic.

Total iron-binding capacity (TIBC): Rarely used.

-Total amount of iron that can bind to transferrin (fully saturated).

-Decreased when excess Fe is present.

-TIBC = unsaturated iron-binding capacity (UIBC) + Fe

-Same as measuring percent transferrin saturation.

Percent transferrin saturation:

-Percent Transferrin Saturation = (Serum Fe/TIBC) x 100

-Normal % saturation: 33%

-As ferritin increases, serum Fe increases, transferrin saturation increases, TIBC decreases.

-As ferritin decreases, serum Fe decreases, TIBC increases, transferrin saturation decreases.

Free erythrocyte protoporphyrin (FEP):

-Protoporphyrin IX + Fe2+ = Heme

-During Fe deficiency, zinc protoporphyrin (ZPP) is produced to increase protoporphyrin level.

-Zinc binds to protoporphyrin instead of Fe.

-FEP is used to differentiate thalassemia from Fe deficiency anemia and ACD.

-FEP is increased in Fe deficiency, ACD, lead poisoning.

-Normal in thalassemia (genetic disorder; abnormal Hb is produced; RBCs are destroyed, causing anemia).

Microcytic anemia:

-Anemias due to abnormal heme synthesis:

-Fe deficiency anemia, anemia of chronic disease, sideroblastic anemia, lead poisoning.

-Due to abnormal globin synthesis:

-Beta thalassemia.

-Fe deficiency anemia: Most common nutritional deficiency.

-Cause:

-Blood loss (mainly males), menstrual period.

-G.I. bleeding due to ulcer, hernia, or cancer.

-Growth spurts, pregnancy, dietary deficiency, malabsorption.

-Symptoms: Fatigue, skin pallor, koilonychia, pica (craving for dirt and ice).

-Differential: Microcytic hypochromic anemia; target cells and ovalocytes present.

-Reticulocyte production index (RPI) < 2

-Possible thrombocytosis (overproduction of platelets).

-Test: Iron studies.

-Serum Fe decreased, ferritin decreased, TIBC increased, transferrin saturation decreased, FEP increased, bone marrow Fe storage absent.

-Treatment: Administer Fe (ferrous sulfate).

-Reticulocytes increase on day 8-10; anemia resolves in 6-10 wks.

-Continue therapy for 6 months after Hb level has returned normal.

-Anemia of chronic disease (ACD):

-2nd most common anemia; most common anemia in hospitalized patients.

-Occurs in patients with chronic infections, inflammations, or neoplasms.

-Apoferritin and macrophages withhold Fe; Fe is present but not available.

-Resolves after underlying chronic disease is treated.

-Differential: Microcytic hypochromic anemia; possible normocytic normochromic anemia.

-RPI < 2

-Test: Iron studies.

-Iron decreased; ferritin increased; TIBC decreased; transferrin saturation decreased; FEP increased; bone marrow storage present.

-TIBC decreased due to inflammation and presence of Fe storage in bone marrow.

-Sideroblastic anemia:

-Cause: Abnormal heme synthesis.

-Presence of ringed sideroblasts in bone marrow.

-Due to increase in free iron in mitochondria surrounding RBC nucleus.

-Presence of dimorphic anemia (2 different cell populations).

-Presence of hypochromic and normochromic cells.

-Or microcytic and macrocytic cells.

-Types: Hereditary or acquired (more common)

-Differential: Dimorphic; increased RDW; pappenheimer bodies and basophilic stippling.

-RPI < 2

-Test: Iron studies

-Fe increased; ferritin increased; TIBC normal-decreased; transferrin saturation increased; FEP variable; bone marrow storage present.

-Lead poisoning:

-Cause: Ingestion of lead-based compounds.

-Associated with hyperactivity, mental retardation, hearing loss, and stunted growth.

-Differential: Microcytic hypochromic anemia, course basophilic stippling.

-Serum iron normal.

-Treatment: Administer lead chelators.

Megaloblastic anemia:

-Cause:

-Folate deficiency (most common), B12 deficiency.

-Coenzyme folate required to form thymine; thymine used to form DNA.

-Folate deficiency results in impaired DNA synthesis.

-Asynchrony: Cytoplasm matures but nucleus does not.

-Symptoms: Enlarged RBCs, WBCs, platelets, hair, nails, mucosal lining.

-Megaloblasts: Oval RBCs.

-Large, premature, nucleated RBC; nucleus resembles salami; chromatin not clumped.

-Destroyed by bone marrow; causing anemia.

-Differential:

-Macrocytic, normochromic anemia; MCV > 99 fL.

-Macroovalocytes, Howell-Jolly bodies, hypersegmented PMNs present.

-Giant bands, decreased retics.

-Increased LDH, bilirubin, iron.

-Bone marrow study:

-Hypercellular marrow (excess cells), erythroid hyperplasia (excess immature RBCs).

-Decreased myeloid to erythroid ratio (M:E ratio of 1:1; normal is 3:1 or 4:1).

Non-megaloblastic anemia:

-Cause:

-Alcoholism (most commoon), liver disease, hypothyroidism.

Vitamin B12: Cyancobalomin

-Only synthesized by microbes in soil and intestines.

-Food source is meat, liver, fish, milk, eggs; daily requirement: 2-5 ��g.

-Body stores 2-5 mg; stored in liver.

-Absorbed in small intestine:

-B12 binds to intrinsic factor secreted by gastric parietal cells (epithelium).

-The resulting complex binds to microvilli; B12 is absorbed; intrinsic factor remains.

-Transcobalamin carries B12 to liver and bone marrow.

B12 deficiency:

-Cause:

-Nutritional deficiency: Lack of animal proteins.

-Malabsorption: Lack of intrinsic factor (pernicious anemia) caused by gastric atrophy (weakening and shrinking of stomach muscles).

-Autoimmune: Ab formed against gastric parietal cells and intrinsic factor.

-Symptoms: abdominal pain, glossitis (swollen tongue, changed color), megaloblastic madness (CNS degeneration)

-Treatment: Inject B12.

-Increased utilization: Hyperthyroidism.

-Consumed by microbes and D. latum.

Schilling test: Only performed if B12 is decreased.

-B12 measurement: EIA.

-3 phases:

-Phase 1:

-Oral dose of B12; administer 57Co-B12; measure 57Co-B12 excreted in urine.

-If tested normal then the lowered B12 is caused by dietary deficiency.

-If abnormal, perform phase 2.

-Phase 2:

-Administer hog IF + 57Co-B12.

-If normal then the lowered B12 is caused by lack of intrinsic factor (pernicious anemia).

-If abnormal, perform phase 3.

-Phase 3:

-Treat patient with antibiotics for 10 days to remove all normal flora.

-Administer 57Co-B12.

-If tested normal, then lowered B12 is caused by parasitic infection.

-If abnormal, then it is due to malabsorption.

Methylmalonic acid (MMA):

-Marker for early B12 deficiency; produced as byproduct during protein metabolism.

-B12 acts as cofactor when converting methylmalonyl CoA to succinyl CoA.

-Methylmalonyl CoA is converted to MMA when B12 is low and MMA increases.

Test battery for diagnosing pernicious anemia:

-Serum B12; MMA, IFBAb (intrinsic factor blocking antibody), parietal cell Ab, gastrin.

Folic acid (or folate) deficiency:

-Body stores last for months; stored in liver.

-Food source: Eggs, milk, leafy vegetables, yeast; overcooking destroys folate.

-Cause:

-Dietary deficiency (most common), alcoholism.

-Malabsorption, increased requirements, drug inhibition, hereditary enzyme deficiencies.

-Tests: Measure both serum and RBC folate.

-Serum folate: reflective of dietary intake.

-RBC folate: reflective of folate stores.

-Methodology: EIA.

Megaloblastoid maturation: Has multiple nuclei less clumped than megaloblast nucleus.

-Present in preleukemia, leukemia, DiGuglielmo's, arsenic poisoning.

-Cannot be treated with B12 or folate; can develop into leukemia.

Macrocytic anemia: Round RBCs.

-Cause: (ALAH)

-Alcoholism (most common)

-Liver disease (associated with target, acanthocytes, and schistocytes)

-AZT (drug used to treat AIDS; associated with decreased lymphs)

-Hypothryoidism

-RPI < 2

Normocytic anemia:

-Symptoms:

-Hypoproliferative anemia; associated with bone marrow hypocellularity (decreased cells).

-Bone marrow cells replaced by fat.

-Aplastic, aplasia, and hypoplastic all refer to bone marrow with decreased hematopoietic cells (RBC-producing cells).

-Cause: Due to inhibition or damage of stem cells:

-If pluripotent stem cell is affected:

-Pancytopenia of WBC, RBC, platelets; causes aplastic anemia.

-If erythroid stem cell is affected:

-Causes pure red cell aplasia.

-Aplastic anemia:

-Types: Acquired or congenital (Fanconi's anemia).

-Cause: Pluripotent stem cell disorder;

-Symptoms:

-Hypocellular bone marrow (< 25%; normal is 70%), pancytopenia.

-Normocytic, normochromic anemia.

- RPI < 2; poor prognosis

-Treatment: Bone marrow transplant.

-Fanconi's anemia:

-Cause: Autosomal recessive disorder.

-Associated with acute leukemia and tumors.

-Leads to aplastic anemia in patients between 5-10 yr.

-Myelophthisic anemia:

-Pluripotent stem cell disorder.

-Differential: Dacrocytes are present.

-Associated with prostate, breast, and stomach cancer.

Pure red cell aplasia:

-Types: Acquired or congenital (TEC).

-Cause: Erythroid stem cell disorder.

-Symptoms: Decrease of erythroid precursors in bone marrow; anemia.

-Diamond-Blackfan Syndrome (erythroblastic hypoplasia):

-Develops in newborn-1 yr old.

-Symptoms:

-Severe normocytic anemia; WBCs and platelets normal.

-Treatment: Transfusion.

-Must differentiate from TEC.

-Transient erythroblastemia of childhood (TEC): Congenital

-Affects newborns and children 1-4 yrs.

-Symptoms:

-Microcytic anemia.

-Associated with infections.

-Treatment: Supportive therapy.

-Anemia of chronic renal disease:

-Normocytic, normochromic anemia; RPI < 2

-Diff: Anisocytosis, Burr cells (echinocytes) present.