Iron, Lead, Porphyrins

Serum Iron

• Measures total serum iron concentration in circulation

• Exhibits diurnal variation

• Reference Range: 45-150 ug/dL

Transferrin

• Directly measures the level of transferrin in blood

• Protein that transports iron around the body

• Reference Range: 200-380mg/dL

TIBC

• Total Iron Binding Capacity

• Measures total amount of iron that can be bound by proteins in the blood

• Indirect measurement of transferrin availability

• Reference Range: 250-400 ug/dL

UIBC

• Unsaturated iron-binding capacity

• The sum of UIBC and serum iron = TIBC

Transferrin

• A calculation that reflects the percentage of transferrin that is saturated with iron (100 x serum iron/ TIBC)

• Reference Range: 20-50%

Serum Ferritin

• Measures total ferritin

• Reference Range: Male - 24-336 ug/L or Female - 11-307 ug/L

Iron Deficiency Anemia

• Decreased hemoglobin production due to decreased total body iron content

• Lab: Microcytic + Hypochromic anemia

• Decreased: Serum Iron, Ferritin, % Saturation

• Increased: Transferrin

Anemia of Chronic Disease

• Decreased hemoglobin production due to decreased amount of free iron

• Decreased bone marrow erythropoiesis

• Decreased: Serum Iron, TIBC

• Increased: Ferritin

Iron Overload

• Decreased: Transferrin

• Increased: Serum Iron, Ferritin, % Saturation

Hemochromatosis

• Increased rate of absorption of iron

• Hyperpigmentation of the skin

• Decreased: TIBC, Transferrin 

• Increased: Total Iron, percent saturation, Ferritin

Lead

• Mostly taken up by RBCs

• Very toxic

• Screening programs for children

• Reference Range: <10 ug/dL

• Children with elevated levels should be tested for IDA

Porphyrins

• By products of heme synthesis and are normally present at low concentration in blood and other body fluid

• Can be measured in urine, blood, stool

Porphyrias

• Uroporphyrin, coproporphyrin, and protoporphyrin

Secondary Porphyrinurias

• Acquired conditions associated with increased excretion of urinary porphyrins, not the result of an inherited biochemical defect in heme synthesis

• Heavy metal poisoning or liver disease