Benign Heme Flashcards
Ataxia Telangiectasia
- rare, neurodegenerative, inherited disease
- impairs cerebellum, causing difficulty with movement and coordination.
- weakens the immune system, causing a predisposition to infection.
- prevents repair of broken DNA, increasing the risk of cancer (especially lymphoma/leukemia)
- sx appear in early childhood when children begin to walk
- caused by a defect in the ATM gene (manages cell’s response to multiple forms of stress including double-strand breaks in DNA)
Bloom Syndrome
Ashkenazi Jewish population
diabetes mellitus
decreased fertility
MDS
Down Syndrome
- overall risk of cancer is not changed, risk of leukemia and testicular cancer is increased and risk of solid cancers is reduced
- leukemia is 10 to 15x more common in Downs:
*ALL is 20x more common
*megakaryoblastic AML leukemia is 500 times more common
- TAM affects 3–10% of infants, resolves without treatment
- After TAM, 20 to 30% risk of developing ALL
HIV marrow findings
ALIP commonly seen (NOT dysplasia) increased plasma cells
Measured CBC parameters
Hgb RBC MCV RDW
Hemolyzed sample- what is still valid
Hgb (after all RBC lysis is the first step in the cyanmethemoglobin method for measuring Hgb)
3 methods automated instruments use to perform cell counts
- Impedance (size) 2. Optical (forward vs light scatter) 3. Combo of these
RBC count
Measures using Coulter principle: cells travel one by one through an aperture across which a current is flowing causing a momentary increase in impedance/electrical resistance V=IR I is constant, R is the increases resistance caused by a red cell, V momentary increase in voltage is interpreted as a single cell which is simultaneously counted/sized Particles measuring 36-360 fL are counted as red cells (includes WBC but their contribution is negligible)
Calculated CBC parameters
Hct MCH MCHC
Hct calculation
Hct= (MCV x RBC)/10
MCH calculation
MCH= (Hb/RBC) x 10
MCHC
MCHC= (Hb/Hct) x 100
Neoplastic causes of increased RBCs
RCC HCC Hemangioblastoma
WBC count
Lyse RBCs then count all particles >36 fL using Coulter principle (plt usually less than 36 fL)
WBC interferences
platelet clumps micromegakaryocytes nRBCs
Platelet count
Particles between 2-20 fL are counted as platelets using Coulter principle
How to fix platelet clumping/satellitism
Recollect sample in sodium citrate New platelet count should be multiplied by 1.1 to correct for dilution factor associated with this anticoagulant
Acanthocytes
- Abetalipoproteinemia
- Severe burns
- Liver dz
- Post-splenectomy
- McLeod phenotype (Kell null)
Fine basophilic stippling
Seen in reticulocytes as artifact of slow air drying
Coarse basophilic stippling
Ribosomal RNA aggregates, indicative of abnormal hemoglobin synthesis (lead poisoning, thalassemia)
Bite cells
Due to removal of Heinz bodies by splenic macrophages (suggestive of G6PD deficiency or drug induced oxidant hemolysis)
Burr cells
Usually artifactual; seen in uremia and pyruvate kinase deficiency
Cabot rings
Remnant of nuclear DNA; remnants of spindle fibers that form during mitosis (seen post splenectomy or in megaloblastic anemia)
Elliptocytes
Seen in iron deficiency anemia and hereditary elliptocytosis



