CLS 442 RBC Lecture 3 Pt. 1

what are the two types macrocytic anemias?

megaloblastic and non-megablastic

what are the causes of megaloblastic anemia

• deprived of vit. B12 & folate

  • ex. vegan, impaired absorption

what are the causes of non-megaloblastic anemia

• variety of deficiencies

  • ex. liver dx, alcoholism

what is commonly seen in non megaloblastic anemia?

• oval macrocytes

• ↑ target cells

• round macrocytes

what are the 2 forms of vit b12 in food?

• Hydroxy-cobalamin

• cyano-cobalamin

what are the 2 forms of vit b12 that are co enzymes?

• methyl-cobalamin

• 5’-deoxyadenosylcobalamin

what steps can vit b12 imparied absoprtion occur in?

• P separation from CBL

• R separation from CBL

• IF-CL binding (lack of IF)

• Malabsorption

• Competition for available vit b12

what occurs when CBL & P don’t split?

• no acidic stomach

• IF def.

• outside stomach problems are rare

in vit b12, if stomach is not intact, what occurs

• IF def. = PA= no B12

what clinical symptoms occur in vit b12 def.?

• prominent neurologic symptoms(memory loss, numbness, tingling in fingers, loss of vibratory sense)

what clinical symptoms occurs in folate def.?

• CNS involvement symptoms not common

• risk of cardiovascular disease due to high serum homocysteine

what is the expected CBC for vit b12 and folate def.?

↓Hgb, Hct, RBCs, WBCs, PLTs

↑MCV, MCH

what is the expected manual diff for vit b12 and folate def.?

• hypersegmented neutrophils

• oval macorcytes

• anisocytosis

• poikilocytosis

• RBC inclusions

what is the expected results below for vit b12 and folate def.?

• absolute reticulocyte count-

• serum total and indirect bilirubin-

• serum LDH-

• absolute reticulocyte count- ↓

• serum total and indirect bilirubin-↑

• serum LDH-↑

what is the expected results below for folate deficiency?

• bone marrow examination-

• serum vit b12-

• serum folate-

• RBC folate-

• serum MMA-

• serum homocysteine-

• antibodies to IF and gastric parietal cells-

• bone marrow examination- erythroid hyperplasia

• serum vit b12- N

• serum folate- ↓

• RBC folate- ↓

• serum MMA- N

• serum homocysteine-↑

• antibodies to IF and gastric parietal cells-absent

what is the expected results below for vit b12 deficiency?

• bone marrow examination-

• serum vit b12-

• serum folate-

• RBC folate-

• serum MMA-

• serum homocysteine-

• holotranscobalamin assay-

• bone marrow examination- erythroid hyperplasia

• serum vit b12- ↓

• serum folate- N or ↑

• RBC folate- N or↓

• serum MMA- ↑

• serum homocysteine-↑

• holotranscobalamin assay- ↓

what 3 specific diagnostic test are present/marked in vit b12 def. :pernicious anemia?

• Abs to IF and gastric parietal cells

• Serum gasrin

• Gastric analysis

what parasite may cause vit b12 def.?

dipyllobothrium latum

what is the RI for WBCs

3.6-10.6

what is the RI for RBC

4.6-6.00

what is the RI for Hgb

14.00-18.00

what is the RI for HCT

40-54

what is the RI for MCV

80-100

what is the RI for MCH

26-32

what is the RI for MCHC

32-36

what is the RI for RDW

11.5-14.5

what is the RI for reticulocytes %?

• 0.5-2.5

what is the RI for reticulocytes #?

• 20-115

what is the RI for plts?

150-450

what is the RI % for neutrophils

50-70

what is the RI % for lymphocytes

18-42

what is the RI % for monocytes

2-11

what is the RI % for eosinophils

1-3

what is the RI % for basophils

0-2

MCV <80 =?

microcytic

MCV 80-100=?

normocytic

MCV >100 fl=?

macrocytic

MCH < 26 =?

less hemoglobin per RBC

MCH 26-34=?

normal amount of Hb

MCH >34=?

large RBCS w/ more Hb

MCHC <32=?

hypochromic

MCHC 32-36=?

normochromic

MCHC >36=?

hyperchromic

RDW <11.5=?

not significant

RDW 11.5-14.5=?

uniform sizes

RDW >14.5=?

anisocytosis

what is the formula for reticulocyte production indec(RPI)?

% retics x patient hct/ref.hct

—————————————-

maturation time

what is pernicious anemia?

an autoimmune disease in which an autoantibody is raised against IF or gastric parietal cells

In PA, through T CD4 mediated response, parietal cells will be destroyed over time(significant decrease in IF secretion into stomach), and these pathologic T cells will also attack and destroy H=/K-AtPase pump on parietal cell membrane leading to reduction in HCL production which is called what?

achlorhydria

what is the diagnosis for PA (3)

• schilling test for absence of IF

• serum gastrin level (marked increase in achlorryhdria)

• detection of Abs against IF(common) or parietal cells

in PA, you could also develop ______?

H. pylori infection (parietal cell destruction)

what is the earliest sign of megaloblastic anemia?

slight macrocytosis

in megaloblastic anemia coexisting _____, _____, or _____ will normalize MCV

• IDA

• chronic inflammation

• beta-thal minor

what is a very important clue for megaloblastic anemia?

oval macrocyte

in megaloblastic anemia, what can be seen on the PBS? (5)

• neutrophil hypersegmentation (important)

• dacryocyte

• RBC fragments

• microspherocytes

• oval macrocytes

what can be seen on the PBS for megaloblastic anemia but it’s rare (4)

• nRBC

• HJ bodies

• basophilic stippling

• cabot ring

what is the effects of cold agglutinin before warming up sample on CBC results? (3)wha

• abnormally high MCV, MCH, MCHC

• low RBC

• high PLT

what is the effects of cold agglutinin after warming up sample on CBC results? (3)

• MCV, MCH, MCHC high

• RBC low despite high Hgb

• mild RBC agglutination

what is the schilling test?

a definitive test useful in distinguishing cobalmain def. due to malabsoprtion, dietary def. , or absence of IF

what does the schilling test measure?

it measures the amount of an oral dose of crystalline vitamin B12 that is absorbed in the gut and excreted in the urine

when a patient is given a dose of ⁵⁷Co-labeled B12 orally with or followed within two hours by an intramuscular inaction of unlabeled vitamin b12, this is termed _______

flushing dose

what is the purpose of the flushing dose

to saturate all cobalamin receptors in the tissue

if the schilling test part 1 is >7.5% of standard dose is excreted in the urine, absorption is _____

normal

If the schilling test part 1 is <7.5%, what is the next step

do part 2 to distinguish between PA and other causes of malabsorption

in part 2 of the schilling test, the oral dose of labeled b12 is accompanied by a dose of ______

intrinsic factor

if part 2 of the schilling test shows >7.5% excretion, what does this indicate for absorption and what is the diagnosis

• absorption is normal with the lack of absorption in part 1 due to lack of IF

• diagnosis is PA

if part 2 of the schilling test is abnormal, what does this indicate

this indicates that the patient likely has another malabsorption defect such a sprue