hematology labs and dx

Question 1

cbc

Answer 1

looks at all blood cells in body
rbc count, hgb, hct, wbc (w/ diff = % - neutrophils, eosinophils, basophils, lymphocytes, monocytes)
% will always = 100, so increase in 1 means decrease in another (maybe not actual count though)
if wbc elevated, may want diff to see what is causing it

Question 2

rbc morphology

Answer 2

color, size, shape
give insight for cause of anemia
MCV = size: normocytic, microcytic (Fe def), macrocytic (megaloblastic = B12 and folate; membrane fragile so dont work as well)
MCHC: mean [] of hgb = hypochromic (low), normochromic - literally look lighter in color if hypo

Question 3

hgb

Answer 3

iron pigment of rbc
trends are more important than values
ex: post op, may be low but trending up

Question 4

hct

Answer 4

% of blood volume composed of rbc
low = anemia, caused by bleeding, bone marrow failure, dietary def, renal disease
high = polycythemia
hemodiluted = fluid retention, HF, KF (so hct looks low bc so much fluid - false low hct)
dehydrated = high hct bc decreased amount of plasma (false high hct)

Question 5

Fe studies

Answer 5

low with Fe deficiency anemia
70% bodily iron in hgb, 30% stored as ferritin and hemosiderin, Fe is bound to transferrin protein
serum transferrin: transports iron, low with Fe deficiency anemia
serum ferritin: stores Fe, low is more sensitive test to determine Fe deficiency anemia
we wouldnt run these tests if we knew cause of anemia (like post op), this is if we are trying to figure out the origin of anemia

Question 6

anemia - other labs and dx

Answer 6

+ antibodies to intrinsic factor = pernicious anemia
serum b12 and serum folate
coombs test
bone marrow exam
stool for guaiac
esophagogastroduodenoscopy (EGD - esophagus, stomach, duodenum) and/or colonoscopy

Question 7

IF

Answer 7

produced by parietal cells in stomach -> allow use of B12
autoimmune if + antibodies

Question 8

stool for guaiac

Answer 8

occult blood - anemia of unknown cause, we immediately think possible lower GI bleed
melena = dark, tarry stool with digested blood
stool + activation agent will say if
+/-
frank blood we can see

Question 9

coombs test

Answer 9

serum blood test to distinguish among hemolytic anemia
direct = attack own rbc; causes: drug, immunity, incompatible blood transF
indirect = screening (type and screen), check for antibodies before transF

Question 10

bone marrow biopsy

Answer 10

red bone marrow produce rbs, esp good in iliac crest
remove bone marrow from locally anesthatized site to eval status of blood forming tissue
I: unexplained anemia, thrombocytopenia, leukopenia (aplastic anemia - problem with precursors to rbc) - pancytopenia
nc: informed consent/procedure explanation, time out, premedicate (for comfort) prn, apply gentle pressure after and assess for bleed post op)
position for iliac crest: on side, fetal position, needle in lower back, just to side of spine