<s>[INST] context: (82-92 FL) (283-Harsh mohan 6th/(439-CMDT-10)Mean corpuscular volume (MCV) =PCV in L/L--------RBC count / L* The normal values is 85 + 8fL (77-93-fL)* MCH normal values - 26-34 pg* MCHC normal values - 31 - 36g/dL* A severely microcytic anemia (MCV < 70 fL) is due to iron deficiency or thalassemia* MCV in infants of 1 month of age is = 90- 110fl**** A severely macrocytic anemia (MCV > 125 fL) is almost always due to either megaloblastic anemia or myelo dysplasia* Aplastic Anemia - Hallmark of aplastic anemia is pancytopenia**, Decreased reticulocytosis, macrocytosis,Neutrophils and platelets are reduced in number, no abnormal cells seen, Hypocellular bone marrow**B12 deficiency MCV is usually strikingly elevated between 110 and 140 fL Vitamin B12 deficiency | ||HaematologicalNeurological manifestations* Megaloblastic anemia(due to demyelination)* Macrocytic anemia||| ||||CerebrumSpinal cordCranial nervePeripheral nerve|||DementiaMyelopathyOptic neuritis| (SACD)/optic atrophyPeripheral neuropathy* Megaloblastic anemia should be treated with both folic acid and vitamin B12 because - folic acid alone causes improvement of hematologic symptoms but worsening of neurological symptoms*** Megaloblastic anemia due to folic acid deficiency is commonly due to- Inadequate dietary intake or increased metabolic demand**. The deficiency of cobalamine is almost always due to malabsorption*** Megaloblastic, anemia in blind loop syndrome is due to Bacterial over growth*** Intrinsic factor of castle is secreted by parietal cells in gastric glandsSCHILLING-TEST - measures cobalamine absorption by measuring urine radioactivity after an oral dose of radioactive cobalamine.The test is useful in demonstrating that the anemia is caused by an absence of intrinsic factor schilling test may be abnormal (usually defined as <10% excretion in 24 hr) in pernicious anemia, chronic pancreatitis, blind loop syndrome, and ileal diseaseFalse positive Schilling test - results are observed in patients with incomplete 24 hour urine collections or renal insufficiency**** Cells are macrocytic, hyperchromic, anisocytosis, hypersegmented neutrophils* ** Bone marrow have decreased myeloid: erythroid ratio (Normal 3:1)* In megaloblastic anemia - nuclear maturation lags behind cytoplasmic maturation* BM shows hypercellularity, erythrocyte precursors at different stages of development is found. Increased megaloblast causes ineffective erythropoisis*** Elevated levels of homocysteine and methylmalonic acid in the serum (This is more sensitive than serum levels of vitamin BI2)*** FIGLU test for Folate deficiency (F for F)* The gene responsible for folic acid transport is situated on chromosome 21*** [/INST] question: MCV is | options: A: Normal value is 82-92 FL B: Increased in aplastic anemia C: Decreased in B12 deficiency D: Normal in Iron deficiency anemia | answer: A </s>