Lab Test Stuff.txt

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Lab Test Stuff.txt
2012-01-05 22:50:13
Lab test medicine

Laboratory tests results
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  1. Lab Exam - CBC
  2. Adult with Hb 106 and MCV 72 - what kind of anemia?
    Microcytic anemia
  3. Differential diagnosis of microcytic anemia? (10)
    #1 Iron deficiency,thalassemias, chronic disease (rare, late stage), sideroblastic, lead, EtOH, drugs, Copper def, zinc poisoning, congenital
  4. #1 worldwide cause of iron deficiency anemia?
    Hook worm
  5. Causes of macrocytic anemia?
    Alcohol #1, B12 or folate, drugs (HIV anti-retrovirals, chemo/MTX, anti-epileptics), Myelodysplastic syndromes MDS, AML/ALL, liver disease, reticulocytosis (hemolysis, bleed, iron therapy), hyperlipidemia, congenital, thyroid, myeloma
  6. Clues about macrocytic anemia from the CBC?
    RDW - Increased (B12, folate, AIHA, drugs) vs Normal (sick bone marrow - MDS, myeloma)
  7. Ancillary tests for work-up of macrocytic anemia
    • #1 smear & retics - to r/o hemolysis and metabolic dz
    • B12 level, RBC folate (or plasma folate), methylemalonate (confirmatory for B12 def), homocysteine level
  8. More ancillary tests for macrocytic anemia - rare
    SPEP, UPEP, liver enzymes, TSH, coombs, haptoglobin, BM biopsy
  9. Normocytic anemia DDx
    Chronic disease, Chronic kidney disease (Epo def), iron deficiency (early), endocrine causes, BM suppression (cancer, aplastic)
  10. Clues on CBC for normocytic anemia w/u
    • RDW - Normal (Chronic disease)
    • WBC/plts - if both low then pancytopenia (aplastic anemia)
  11. 2 best ancillary tests for Normocytic anemia w/u
    Start with smear and retics
  12. If smear and retics not helpful in normocytic workup, what next?
    Do Cr to rule out CKD, but otherwise consult heme if going further
  13. Clues on CBC for Microcytic anemia
    • RDW - increased (Fe def), Normal (thalassemia, chronic disease)
    • Count - Increased (Thalass), Decreased (Fe def)
  14. Single best ancillary test for microcytic anemia
    Ferritin! But increased in inflammatory process (more common with inpatients)
  15. How to interpret ferritin results?
    • <10 - Dx for Fe deficiency, <30-40 (LR 11) very sense and spec for iron deficiency. If >100 then not Fe def (LR 0.1).
    • So if between 40 and 100 then can't tell.
  16. If Ferritin is equivocal for microcytic anemia work-up?
    • TIBC, Transferrin sat, Fe level (if ferritin between 40-100)
    • Hb electrophoresis if suspect thalassemia, hemoglobinopathy
  17. When to be more hasty with tests in microcytic anemia?
    If pregnant, want to Dx thalassemia or genetic Hb-opathy sooner than later, so do hb electrophoresis (SPEP) sooner.