Test 3: Disorders of Iron and Heme Metabolism Flashcards
The average adult has total body iron content of _______ mg
____ is found in hemoglobin
____ is found in bone marrow, liver, and spleen
3500-4000 mg
• 2/3
•1/3
Where does the majority of iron come from?
Recycling 
The minimum daily iron requirement for adults is ___ mg
1
Daily iron requirements are affected by what three things? 
- chronic blood loss
• Increase need
• Inadequate intake
Serum Fe levels exhibit both monthly and diurnal (daily) variation.
When should labs be drawn for iron studies?
First thing in the morning and fasting
Iron is ingested in foods as Fe__+ (_________) form. 
3, ferric
Stomach acid reduces Iron to Fe__+ (________) form so it can be absorbed in the gut.
2, ferrous
- gut mucosal cells oxidize back to Fe3+ form, enters the bloodstream, and is transported by transparent for distribution to buy tissues, or for storage in the bone marrow, liver, or spleen
______ atoms of ferric iron can combine to one transferrin molecule.
2
____% of iron carried by transferrin is used for heme synthesis
80
Iron not utilized by erythropoiesis is stored as _________ or _________. 
Ferritin or hemosiderin
____________ is the major form of storage iron. It is water soluble and is easily utilized by the body. Seen only via electron microscope. 
Ferritin
__________ + ___________ = ferritin
Apoferritin, Fe
____________ is not water soluble and is less readily available to the body.
Hemosiderin
This iron form represents Aggregates of iron and can be seen with Prussian blue stain
Can become available in iron deficient patients
Hemosiderin
What stain is used for hemosiderin?
Prussian blue stain for iron
What is included in the standard Fe panel?
-serum Fe
-TIBC
-Serum ferritin
-Percent transferrin saturation
This is a measure of transferrin–bound iron
Serum Fe
(NR=50 - 160 ug/dL)?
*assays has poor sensitivity for IDA, due to the disease’s various stages
Total amount of iron that can be bound by transferrin. It is effectively an indirect measurement of transferrin concentration
- total iron binding capacity (TIBC)
(NR= 250 - 400 ug/dL) 
increased TIBC means the body….
wants more iron! 
TIBC:
Add known amount access iron to patients Sera to saturate all transferrin molecules present then remove excess and…. 
Measure what remains
TIBC does what in IDA? 
???
Transferrin Increases when Fe __________. 
Decreases.
-In order for body to scavenge up any available iron atoms 
Immunoassay which evaluates body iron stores. Despite the fact that ferritin is intracellular its concentration in circulation is usually proportional to the amount of iron in storage
Serum ferritin 
What is the advantage and disadvantage of serum ferritin? 
This is the first lab test to become abnormal when iron stores decrease (Even before RBC morphology changes) 
Ferritin is an acute phase reactant so it’s elevated during any inflammatory response 
What is the normal range for serum ferritin? 
40-400 ng/mL
What might a patient’s ferritin level be with an exacerbation of SLE who also had an IDA? 
Normal
Is functionally measured as the maximum amount of iron that is Bound in plasma or serum
% transferrin saturation
(in other words, “how many transferrin molecules are full”?
How is percent transferrin saturation calculated? 
= serum iron / TIBC x 100%
What is the normal range for % transferrin saturation? 
20-55% saturation
What would percent transferrin be in IDA?
Decreased
What would percent transferrin saturation be in iron overload? 
Increased
How do the Free Erythrocyte Protoporphyrin (FEP) or Zinc  Protoporphyrin (ZPP) tests work?
-when iron is not available to be incorporated into protoporphyrin ring to form heme, access portoporphyrins form
-these excess rings complex with zinc to form zinc protoporphyrin (ZPP)
-The ZPP value correlates inversely with the ferritin level
A The worse the IDA, the _______________ the ZPP level.
Higher
More Protoporphyrin is left over to bind with zinc (due to decreased iron binding)
What is a good test to differentiate IDA from thalassemia? 
Free erythrocyte protoporphyrin (FEP) or Zinc protoporphyrin (ZPP) test *
How is FCP/ZPP test measured? And what is the normal range?
Fluorometrically
< 80 ug/dL
Measurement of transferrin receptors
Soluble transferrin receptor test 
Soluble transferrin receptors are ____________ related to the amount of body iron. 
Inversely
With the lack of intracellular iron, regulatory proteins increase the synthesis of ______________ receptors.
transferrin 
Severe IDA __________ transferrin receptors
Increases
What test can be used to distinguish IDA from anemia of chronic inflammation? 
Soluble transferrin receptor test
- soluble transferrin receptor test levels remain normal in anemia of chronic Inflammation
What is the definition of anemia according to WHO criteria for men and women? 
• Men: Hb < 13.0 g/dL or Hct < 40%
• Women: Hb < 12.0 g/dL or Hct < 36%
What are useful measurements For assessing anemia?
• MCV (mean corpuscular volume): 80-100 f
• RDW (red cell distribution width): increased value indicates
RBCs of differing sizes
• Reticulocytes: indicates the bone marrow’s ability to respond
Worldwide what is the most common type of anemia that affects 2 billion people? 
Iron deficiency anemia (IDA)

What are the three ways IDA can occur?
-State of increased physiologic demand (growth or pregnancy)
-inadequate intake (deficient diet or absorption issues)
-chronic blood loss (Ulcers, menstrual flow, parasites) 
What age does prenatal iron stores run out at?
Three months (3-6 months) 
what are common Symptoms of all severe anemia?
dyspnea and dizziness