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72 Cards in this Set

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  • Back
Body Iron regulation (absorbance of iron into gut) is monitered by...
negative feedback with hepcidin
The three most commonly look at lab assessments of iron are?
Hgb, MCV, and RDW
A ____ MCV together with an ______ RDW is strongly suggestive of ______
Low; increased; iron deficiency
When you have a strongly suggestive iron deficiency along with an increased erythrocyte porphyrin, it can be considered
diagnostic of an iron deficiency
What is the gold standard for storage iron assessment
Bone marrow examination
Name the 5 tests for Iron assessment other than Bone marrow examination
1.serum iron
2.serum transferrin
3.transferrin receptor(TfR)
4.Iron-binding capacity
5.ferritin
Sensisitve to the stage of mild iron deficiency; levels decrease after body stores are fully depleted but before Hgb levels droup; level are transiently increased after oral iron ingestion
Serum Iron (SI)
Serum/plasma iron >3500 ug/L (350 ug/dL) idicates
significant exposure or overdose of iron
A glycoprotein that binds iron very tightly but reversibly
transferrin
When transferrin in not bound to iron, it is known as
apo-transferrin
Circulation form of iron; increased in iron deficiency
serum Transferrin (Tf)
_____ umol of transferrin bind to ____ umol of iron
2;1
the ratio of serum iron to iron binding capacity; the most accurate indicator of iron supply to the bone marrow
Transferrin saturation (TS)
Iron deficiency is seen when % saturatioin is...
<10-12%
Whats the percent saturation if you have 9 transferritin molecules and 13 Fe3+ molecules what is percent saturation?
72%
Determines cells need for iron, this circulating form of iron is proportional to rate of erythropoeisis, becomes elevated in iron deficiency
sTfR serum transferrin
sTfR is used for differntial diagnosis of what two microcytic anemias?
iron deficiency from anemia of chronic disease
explain the transferrin cycle in transferritin receptor
transferrin bind to cell and enters cell, Fe released in cell, apo- protein released out of cell
storage form of iron
serum ferritin (SF)
1ug/L of serum ferritin binds to corresponds to what?
8-10 mg of storage iron
What are the levels for iron deficiency in serum ferritin?
<12ug/L for adults
<6 for children and <12 ug/L in babies
Serum ferritin acts as an acute phase reactant how?
upon inflimmation, the acute ferritin levels will change (increase or decrease)
what is the R/F ratio?
serum transferritin receptor/ serum ferritin (receptor to serum ferritin ratio)
used to provide an estimate of iron stores; this ratio is affected by inflammatory processes
R/F ratio
in the R/F ratio, which is not affected by oral contraceptives or iron intake?
sTfR
When is the best time to collect an iron specimen?
morning
Iron has a _______ variation
values are normal_______
values are low ________
diurnal; in the am; in the pm
Why can't you have a hemolyzed sample in an iron assessment?
all the iron in the Hgb is released into the plasma
What are different methods for measuring TIBC?
1. saturate all binding sites with excess Fe3+
2. bind Fe3+ to free sites
3. remove Fe3+ left in serum, measure per iron method
how do you calculate unbound IBC?
unbound IBC= TIBC- serum Fe
formula for % saturation
(serum iron/ TIBC) x100
name different ferritin assays (5)
Immunoturbideimetric assay
electochemiluminescence immunoassay
immunoradiometric assay
radioimmunoassay
enzyme-linked immunosobenst assays
immunological methods are used in what assay
transferrin
immunoenzymometric assay and sensitive monoclonal ELISA techniques are used in
sTfR assays
Blocks heme synthesis pathway in 3 spots
Lead poisoning
What are collection requirements when testing for lead?
lead free needle for collection, collected in a royal blue top tube,EDTA is common anticoagulant used, capillary blood not recommended
What is best for detection of lead exposure?
Whole blood lead measurement
What are the levels for iron testing in whole blood?
<10 mcg/dL normal in adults
>30 mcg/dL in adults indicates significant exposure
-not sensitive indicators of low level lead (<35 mcg/dL)
-should not be used as screeing test to detect lead- exposed children
valuable test as a screening test for iron deficiency and for management and follow up care of children with confirmed elevated blood lead leavels
Free erythrocyte protoporphyrin assay levels(EPP)
BLL-EP pairs useful in follwing long term trends in lead absorption and in evaluating the question of internal redistribution of lead after______________
chelation therapy
-considered a supplemental lead test
-not specific due to iron deficiency and anemia of chronic disease
-sensitivity limits of 25 mcg/dL
zinc protoporphyrin (ZPP)
Free erythrocyte protoporphyrin chelates ____ and forms ____________
zinc; zinc protoporphyrin
The level of zinc protoporphyrin in the RBC is directly related to?
the level of lead in blood
Cutaneous erythropeitic porphyria is commonly known as
werewolf syndrome
-Only cure is bone marrow
-symptoms include blackening of teeth, spleen liver and heart damage
-treatment without bone marrow includes blood transfusions every three weeks for the rest of life
congenital erythropoietic porphyria (CEP)
In cutaneous erythropoietic porphyria symptoms include
brown teeth, thickening of the forehead, jaw, lips, and cheeks, bone fragmentation, extreme hair grouth over entire body, delayed learning
cyclic compounds formed by methylene linkage of 4 pyrole rings
porphyrins
Three porphyrins of clinical significance are
uroporphyrin, coporphyrin, protophyrin
-Pyrroles nuclei substitution by carboxyl groups alter the solubility
-deposit in the skin injured when exposed to UV light
Chemical properties of porphyrins
porphyrins that are soluble in water and cause late bullous lesions
Uroporphyrin and coproporphyrins
this porphyrin is soluble in lipids and insoluble in water. concentrates are more in cellular membranes, inflammatory reactions with burning sensations after exposure to sunlight
Protoporphyrin
_______ is eliminated through urine
_______ is eliminated through in feces
_______ is eliminated through both methods
uroporphyrin; protoporphyrin; coproporphyrin
Porphyrin diseases are divided into what three categories?
pophyrinuria, porphyrinemia, porphyrias
moderate increase in urine coproporphyrin production
porphyrinuria
increase in protoporphyrin concentration in RBCs
porphyrinemia
abnormal porphyrin metabolism and an overproduction or accumulation of heme precursors in body
porphyrias
porphyrinuria is caused by (4)
liver damage, accelerated erythropoiesis, infection, lead intoxication
porphyrinemia is caused by (4)
iron deficiency, impaired iron absorption, chronic infection, lead intoxication
-Inherited or acquired disorder
-results in abnormal porphyrin metabolism and an overproduction of heme precursors
-common feature is the excess accumulation of porphyrins or porphyrin precursors in the body
Porphyria
-acquired caused by liver disease or toxicity from heavy metals or drugs
-inherited is result of a deficiency of an enzyme in heme synthesis pathway
porphyria inherited or acquired disorders
Hepactic porphyria is a defect in...
the porphyrin metabolism in liver
erythropoietic porphyria is defect in...
blood producing tissues (bone marrow)
porphyria characterized by skin manifestations
cutaneous porphyria
porphyria characterized by sudden attacks of pain and other nuerological symptoms
acute porphyria
-hereditary defect of hepatic prophobilinogen deaminase (PBG-D)
-high deltaALA in urine
- high porphobilinogen in urine
AIP (acute intermittent porphyria)
-also known as Gunther's disease
-defect in uroporphyrinogen III cosynthase
-urine a port wine color
-High ALA
-high uro and coproporophyrinogen
CEP (congenital erythropoietic porphyria)
-20-30% decrease in ferrochelatase
-protoporphyrin accumulates in the bone marrow, red blood cells
-no excess porphyrins in urine
EPP (erythropoietic protoporphyria)
-dark red or purple color
-oxidized by light
-flouresce in organic solutions under UV light
properties of porphyrins in urine
-Most commonly used test for measurement of porphobilinogen
- uses Ehrlich's reagent
Watson-Schwartz test
What reaction takes place in the watson- schwartz test
p-dimethylaminobenzaldehyde (PBG)+ehrlich's---> red color
-flouresce principle
-add amyl alcohol, etherl ether and glacial acetic acid
-shake, allow to seperate
-upper, organic layer will flourescence if porphyrins are present
porphyrin test
-Not a very sensitive test, but used for kids in lead poisoning
- reference values 20-80 ug/dL RBC
Hematofluorometer