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Who discovered Hemoglobin?
- Felix Seyler 1862
- Proved respritory Protein.
- True coloring matter of blood.
- O2 Transport pigment found in RBCs.
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Function of Hemoglobin.
- O2 to tissues.
- Returns CO2.
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HGB as a buffer.
Acts as a proton acceptor and a proton donor.
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HGB Clinical significance.
- O2 transport capacity.
- RBC volume.
- RBC Number.
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Normal HGB numbers
- Female 14 (+/- 2 g/dl)
- Male 16 (+/- 2 g/dl)
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Decreased HGB Anemias
- Microcytic= Iron Deficiency
- Normocytic= Acute Hemorrhage.
- Macrocytic= Pernicious Anemia
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Decreased HGB (non Anemic)
- All Leukemias except CML
- Altitude (nonpathological)
- Over age 50 (nonpathological)
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Increased HGB
- Dehydration and Shock
- Polycythemia Vera.
- Hemochromacytosis
- Newborns (nonpathological)
- Altitude (nonpathological)
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HBG Compound.
Composed of carbon & Hyrdrogen.
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HGB Structure.
- 4% Heme (4 hemes)
- 96% Globin (1 globin)
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Heme Structure.
- Tetrapyrole Ring
- 4 Pyrole rings connected by methane bonds.
- Pyrole ring is 4 carbon ring + nitrogen.
- Fe +2 in the center of ring.
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Structure of globin.
- Tetramer
- 4 polypeptide chains (monomers) in 2 polypeptide units (dimers)
- 2 alpha chains and 2 beta chains.
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Globin formed by ?
Cytoplasmic Ribosomes of RBCs
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Heme is formed in the?
Mitochondria & Cytoplasm of RBCs
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Formation of HGB timeline.
- Begins in the Rubricyte Stage.
- 65% formed in the metarubricyte stage.
- 35% formed in the reticulocyte stage.
- None formed in mature erythrocyte.
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Formation of 4 monomers (polypeptide chains) occurs in?
- Cytoplasmic Ribosomes.
- 2 Alpha & 2 Beta arranged into Tetramer.
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Each monomer contains how many amino acids?
141-146
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Synthesis of Heme
- Begins in mytochondria from succinyl Coenz A (vit. B6 needed)
- Converted to Delta ALA which diffuses into cytoplasm then converted to Protoporphyrin.
- Protoporphyrin transported to the mitochondria where combined w/ Fe + 2 to form Heme.
- Heme transported back to cytoplasm where combined with globin to for HGB.
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Embryonic HGB
- First HGB formed
- Formed during 1st 12 weeks of gestation.
- globin is composed of 2 Zeta Chains +
- 2 Beta, 2 Gamma or 2 Delta Chains.
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Fetal HGB
- Called HGB F
- Second formed HGB 3-6 months
- 1-2% of Adult HGB is HGB F
- Globin is 2 Alpha & 2 Gamma Chains.
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Adult HGB
- 2 Types
- 96% HGB A1
- Globin is 2 Alpha & 2 Beta Chains
- 2-3% HGB A2
- Globin is 2 Alpha & 2 Delta Chains
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Abnormal HGB
- HGB S
- HGB C
- HGB H
- HGB E
- Burt's HGB
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Gamma Chains
Amino Acid #136 of beta chains is substituted w/ either Alanine or glycine.
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Delta Chains
8 Amino acids on beta chains substituted.
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Heriditary Persistance of Fetal HGB (HPFH)
- Rare Condition
- Produces large amounts of HGB F into Adulthood
- Homozygous (100% HGB F)
- Heterozygous (30% HGB F)
- Normal (1-2% HGB F)
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HGB S
- #6 amino acid on beta chains is replaced with Valine.
- HGB is insoluble in low O2 concentrations.
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HGB C
# 6 Amino Acid on beta chains is replaced w/ lysine.
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HGB Inheritance
- Inheritant 1 gene for HGB from each parent.
- Co-dominant genes.
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Oxyhemoglobin
O2 bound to HGB.
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HGB Inheritance Patter
- Normal A-A
- Sickle Cell Disease S-S
- Sickle Cell Trait A-S
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Deoxyhemoglobin
CO2 Bound to HGB
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Reduced Hemoglobin
H bound to HGB
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Carboxyhemoglobin
- CO bound to HGB
- Can't carry O20.5% normal
- 1-10% in smokers
- 20-30% CO poisoning
- >40% ussually deadth
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Sulfhemoglobin
- Sulfer bound to HGB.
- Sulfa Drugs oxidize HGB wich perpetuate out as heinz bodies.
- Can't carry O2
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Methemoglobin
- Iron in HGB oxidized to ferric state.
- Can't carry O2.
- May be inherited as autosomal dominant trait (HGB M disease) in which Tyrosine substituted for histadine on either alpha or beta chains.
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Breakdown of HBG
- Iron returns to bone marrow.
- Globin breaks down into amino acids.
- Porphyrin ring oxidized to Biliverdin (green) to unconjugated biliruben (yellow)
- Biliruben detoxified in the liver then released into intestines.
- Bacteria reduce it to Urobilinogen then Urobilin.
- Some reabsorbed and excreted by kidneys.
- Most excreted as feces.
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Gravity method of HGB Measurment.
- 2 Solutions of Copper Sulfate
- Males is SP GR 1.055
- Females with SP GR 1.053
- If the drop sinks HGB is >13.5 for men and >12.5 for woman.
- If drop floats HGB is too low.
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Sources of Error with Hemoglobincyanide
- Lipemic Sample
- HGB S/HGB C
- High WBC count
- Doesnt measure SulfHGB
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3 Normal A1 Fractions
- HGB A1a
- HGB A1b
- HGB A1c
- HGB A1c is predominant fraction 3-6% is normal
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Glycosylated Hemoglobin.
- HGB with glucose attached to terminal Valine.
- Formed over weeks of continuously elevated blood sugar.
- Diabetics have 6-12% GHgb
- <10% is good control for diabetic
- >10% is out of control.
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Hematacrit definition
Ratio of RBC volume to total blood volume.
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Calculation of HCT
RBC Volume / Total Volume x 100%
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Calculation of Hgb from HCT
1/3 HCT is Hemoglobin
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Hematocrit Increase
- Dehydration and Shock
- Burns
- Polycythemia
- Altitude (nonpathological)
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Pathological decrease of Hct
- Anemia
- Hemorrhage
- Pregnancy
- Edema
- Cirrhosis
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Nonpathological Decrease of HCT
- Surgery with Blood Loss
- Blood Donation
- Over 50 years of age
- Altitude
- Recumbent Patient
- After Meals
- Long Distance Runners
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Age affecting Values
- Higher in Newborns
- Lower in kids 1-12
- lower over age 50
- Lower in Females
- higher in males
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Normal HCT Ranges
- Men 42 +/- 6
- Female 47 +/- 8
- Surgery 30
- Nonsurgery 24
- Panic Value 11
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Collection Method for HCT
- Heparinized Micro Tubes
- May collect in edta container
- Centrifuge Stat
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Centrifuge Microhematocrit.
- 3 minutes @ 12000 g
- Measure within 10 minutes.
- Duplicate tests must agree within 1-2%
- Look for Hemolysis, Jaundice, Lypemia.
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Trapped Plasma
Plasma that surrounds RBCs after spun
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Buffy Coat
Layer in between RBCs and plasma composed of WBC and platelets.
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Calculate RBC from MCV Values
HCT= RBC x MCV / 10
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