Labs

Question 1

Hb

HCT

RBC

Rule of 3’s

Answer 1

• Hb - conc of Hb in blood
• HCT - proportion of RBCs compared to total vol (RBCs + plasma)
• RBC - red blood cell count

RBC (3) = Hb and Hb(3)= HCT

Question 2

MVC

Answer 2

• meas of avg size of RBCs (macrocytic, normocytic, microcytic)

Question 3

Reticulocyte Count + Correction

Answer 3

• Amount of absolute reticulocytes - hypo, hyper or normoproliferative
• Corrected Reticulocyte Count = retic % given x (Hb of pt / normal Hb for gender)

Question 4

RPI

Answer 4

• Then decide if there are shift cells (inc IRF) and if so you need to measure RPI (reticulocyte proliferation index)
• RPI = corrected retic & / retic maturation time (dep on Hb)
  - Hb 15 = 1 day
  - Hb 12= 1.5 days
  - Hb 8 = 2 days
  - Hb 5 = 2.5 days
• RPI < 1 hypo-proliferative and RPI > 1 hyper-proliferative

Question 5

IRF

Answer 5

immature reticulocyte fraction

ratio of immature reticulocytes: total reticulocytes (found by meas rRNA)

Question 6

CHr

Answer 6

mean reticulocyte Hb content - sensitive indicator of iron availability

Question 7

MCH

MCHC

RDW

Answer 7

MCH -amount of Hb in ea RBC

MCHC -based on Hb and HCT

RDW (size variability)

Question 8

Iron Labs

Answer 8

Serum iron

Ferritin - represents stored iron

TIBC - unsaturated carrier

• In iron def, there is dec iron and ferritin but inc TIBC b/c more is made by liver and not being used
• In anemia of chronic disease, iron is trapped so low iron and low TIBC (liver stops making it) but high ferritin (high stores)

Question 9

Serum Homocysteine and Methylmalonic Acid

Answer 9

• If both elevated - B12 def

- If only homocysteine elevated - folic acid def

Question 10

Schilling Test

Answer 10

• Radioactive B12 given then subQ block of B12 receptors; if >8% in URINE then normal if <8% then problem w/ absorption (did not get out of GI –> circ –> urine)
• If corrected w/ admin of radioactive B12 bound to IF then know it is pernicious anemia; if still not corrected then bacterial overgrowth, tapeworm, illeal resection likely
• If corrected w/ admin of radioactive B12 w/ pancreatic enzymes then pancreatic insufficiency

Question 11

General Labs for all Megaloblastic Anemias

Answer 11

dec reticulocyte count, elevated LDH, inc bilirubin, dec haptoglobin

Blood smear = macro-ovalocytes, hyper-segmented PMNs, giant bands, giant platelets

Question 12

Coomb’s Test

Answer 12

• Direct anti-globulin test - incubate w/ anti-IgG and/or anti-complement antibodies; look for agglutination
• Indirect - incubate normal RBCs w/ patient’s serum and add anti-IgG or anti-complement; this would detect target proteins in patient serum
  • Can be used to see if someone would react to blood transfusion