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50 Cards in this Set
- Front
- Back
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Transferrin, is it a neg or pos acute phase, how many Fe3+ can bind, and normally how much saturated?
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- Major plasma iron transport protein
* releases iron to the bone marrow - Negative acute phase protein - 2 Fe+3 per transferrin molecule - Normally ~ 1/3 saturated |
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Transferrin method
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immunoassay, nephelometry
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What is Total Iron Binding Capacity and what kind of anitcoagulant needed?
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- The total amount of iron that can be bound to transferrin and other minor iron binding proteins present in the serum or plasma (heparinized)
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TIBC Method, UIBC =, TIBC =, %sat =, transferrin =
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1) a. add excess Fe+3 to saturate the transferrin molecule
b. remove excess (unbound) iron by precipitation with MgCO3 c. measure total iron (next slide please) 2) a. add excess iron to sample b. detect unbound iron using a chromogen which reacts with unbound iron c. UIBC = iron added – unbound excess iron d. TIBC = UIBC + serum iron - % Saturation = total iron/TIBC x 100% - [transferrin] = TIBC ug/dl x 0.7 |
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Iron Testing: what form is iron measure as?
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- Iron is measured as Fe+3 bound to transferrin
- Total iron determination * Acidification releases Fe+3 from binding proteins * Reduction of Fe+3 to Fe+2 * Fe+2 complexes with ferrozine, ferene, or bathophenathroline -> chromogen |
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Ferritin, about what % is in circulating blood?
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- major iron storage compound
- Bone marrow, spleen, liver ~1% is in circulating blood |
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Ferritin increased in what?
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- chronic infections
- malignancy - viral hepatitis - iron overload |
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Ferritin decreased in what?
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- iron deficiency anemia
- malnutrition |
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What is the first marker to decrease in early stages of iron deficiency?
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Ferritin (may be masked by malignancy, infection, inflammation)
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Iron is physiologically active, only in the ferrous form in:
A.) cytochromes B.) ferritin C.) hemoglobin D.) transferrin |
C.) hemoglobin
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Which pattern most likely represents iron deficiency?
A.) Decreased ferritin, increased transferrin, increased serum iron B.) Increased ferritin, increased transferrin, increased serum iron C.) Decreased ferritin, increased transferrin, decreased serum iron D.) Decreased ferritin, decreased transferrin, decreased serum iron |
C.) Decreased ferritin, increased transferrin, decreased serum iron
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Which statement about iron is NOT true?
A.) TIBC may be calculated from the transferrin concentration B.) Myoglobin has a higher affinity for iron than hemoglobin C.) Transferrin in serum is typically 99% saturated with iron D.) Serum iron is typically higher in males than females |
C.) Transferrin in serum is typically 99% saturated with iron
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iron in Iron Def Anemia
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decrease
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transferrin in IDA
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increase
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% saturation in IDA
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decrease
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ferritin in IDA
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decrease
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iron in hemachromatosis
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increase
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transferrin in hemachromatosis
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decrease
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% saturation in hemachromatosis
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increase
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ferritin in hemachromatosis
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increase
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iron in malignancy
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decrease
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transferrin in malignancy
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decrease
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% saturation in malignancy
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decrease
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ferritin in malignancy
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increase
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iron in chronic infection
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dec
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transferrin in infection
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dec
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% sat in infection
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dec
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ferritin in infection
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inc
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iron in viral hepatitis
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inc
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transferrin in viral hepatitis
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inc
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% sat in viral hepatitis
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N/inc
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ferritin in viral hepatitis
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inc
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Bilirubin metabolism
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heme -> biliverdin -> bilirubin -> conjugated bilirubin: bilirubin diglucuronide
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Bilirubin
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pigmented breakdown product of heme
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Ref range of bilirubin
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Normal: Total 0.2-1.0 mg/dl
Conjugated: 0.0-0.2 mg/dl |
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Jaundice, icterus
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- yellow pigmentation of sclera, skin due to elevated bilirubin levels
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Prehepatic jaundice, caused by what condition, what is total bilirubin, direct/total, and what kind predominates?
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- hemolytic anemia
- total bilirubin NOT > 3.5 mg/dL - direct/total <0.2 - unconjugated bilirubin predominates |
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What happens in hepatic jaundice and what causes it?
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- impaired uptake, conjugation, & excretion by hepatocyte
- Hepatitis & hepatic necrosis |
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What happens in Posthepatic jaundice, direct/total, and what kind predominates
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- obstruction of flow of bile from the liver
- direct/total >0.5 - conjugated bilirubin predominates |
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Kernicterus, total bilirubin, treatment?
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- increased bilirubin in newborns -> CNS symptoms
- immature liver: minimal activity of conjugating enzyme - Total bilirubin > 15 mg/dl - treatment: phototherapy * photooxidation of bilirubin -> water-soluble non-toxic form |
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Direct spectrophotometric determination of total bilirubin, what interferes?
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- Abs 455 nm
- correction of Hb Abs by subtracting Hb abs @ 575 nm - lipochromes interfere - Newborn screening: no lipochromes present in newborn serum |
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POCT bilirubin
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noninvasive transcutaneous bilirubin
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Gilberts syndrome
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- inherited
- common Decreased bilirubin uptake by the liver: decreased conjugated bilirubin |
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Dubin-Johnson Syndrome
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- Autosomal recessive: increased conjugated bilirubin
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Crigler-Najjar syndrome
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- UDP-glucuronyl transferase deficiency
- increased unconjugated bilirubin - If autosomal dominant: lethal |
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Total Bilirubin Method
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- Diazo rxn
- caffeine reagent (accelerator) + diazotized sulfanilic acid -> azobilirubin (blue green) 600 nm - reaction stopped @ 10 min with addition of acid/base |
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Conjugated bilirubin method
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- Diazo rxn
- reaction above in dilute HCl - no accelerator - reaction stopped - base added to intensify color (azobilirubin) |
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Unconjugated =
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Unconjugated = Total - conjugated
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Direct
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Conjugated
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Indirect
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unconjugated
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