Hemoglobin & Hematocrit


Who discovered Hemoglobin?


Felix Seyler 1862Proved respritory Protein.True coloring matter of blood.O2 Transport pigment found in RBCs.


Function of Hemoglobin.


O2 to tissues.Returns CO2.


HGB as a buffer.


Acts as a proton acceptor and a proton donor.


HGB Clinical significance.


O2 transport capacity.RBC volume.RBC Number.


Normal HGB numbers


Female 14 (+/- 2 g/dl)Male 16 (+/- 2 g/dl)


Decreased HGB Anemias


Microcytic= Iron DeficiencyNormocytic= Acute Hemorrhage.Macrocytic= Pernicious Anemia


Decreased HGB (non Anemic)


All Leukemias except CMLAltitude (nonpathological)Over age 50 (nonpathological)


Increased HGB


Dehydration and ShockPolycythemia Vera.HemochromacytosisNewborns (nonpathological)Altitude (nonpathological)


HBG Compound.


Composed of carbon & Hyrdrogen.


HGB Structure.


4% Heme (4 hemes)96% Globin (1 globin)


Heme Structure.


Tetrapyrole Ring4 Pyrole rings connected by methane bonds.Pyrole ring is 4 carbon ring + nitrogen.Fe +2 in the center of ring.


Structure of globin.


Tetramer4 polypeptide chains (monomers) in 2 polypeptide units (dimers)2 alpha chains and 2 beta chains.


Globin formed by ?


Cytoplasmic Ribosomes of RBCs


Heme is formed in the?


Mitochondria & Cytoplasm of RBCs


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.


Formation of 4 monomers (polypeptide chains) occurs in?


Cytoplasmic Ribosomes.2 Alpha & 2 Beta arranged into Tetramer.


Each monomer contains how many amino acids?


141-146


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.


Embryonic HGB


First HGB formedFormed during 1st 12 weeks of gestation.globin is composed of 2 Zeta Chains +2 Beta, 2 Gamma or 2 Delta Chains.


Fetal HGB


Called HGB FSecond formed HGB 3-6 months1-2% of Adult HGB is HGB FGlobin is 2 Alpha & 2 Gamma Chains.


Adult HGB


2 Types96% HGB A1Globin is 2 Alpha & 2 Beta Chains2-3% HGB A2Globin is 2 Alpha & 2 Delta Chains


Abnormal HGB


HGB SHGB CHGB HHGB EBurt's HGB


Gamma Chains


Amino Acid #136 of beta chains is substituted w/ either Alanine or glycine.


Delta Chains


8 Amino acids on beta chains substituted.


Heriditary Persistance of Fetal HGB (HPFH)


Rare ConditionProduces large amounts of HGB F into AdulthoodHomozygous (100% HGB F)Heterozygous (30% HGB F)Normal (1-2% HGB F)


HGB S


#6 amino acid on beta chains is replaced with Valine.HGB is insoluble in low O2 concentrations.


HGB C


# 6 Amino Acid on beta chains is replaced w/ lysine.


HGB Inheritance


Inheritant 1 gene for HGB from each parent.Co-dominant genes.


Oxyhemoglobin


O2 bound to HGB.


HGB Inheritance Patter


Normal A-ASickle Cell Disease S-SSickle Cell Trait A-S


Deoxyhemoglobin


CO2 Bound to HGB


Reduced Hemoglobin


H bound to HGB


Carboxyhemoglobin


CO bound to HGBCan't carry O20.5% normal1-10% in smokers20-30% CO poisoning>40% ussually deadth


Sulfhemoglobin


Sulfer bound to HGB.Sulfa Drugs oxidize HGB wich perpetuate out as heinz bodies.Can't carry O2


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.


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.


Gravity method of HGB Measurment.


2 Solutions of Copper SulfateMales is SP GR 1.055Females with SP GR 1.053If the drop sinks HGB is >13.5 for men and >12.5 for woman.If drop floats HGB is too low.


Sources of Error with Hemoglobincyanide


Lipemic SampleHGB S/HGB CHigh WBC countDoesnt measure SulfHGB


3 Normal A1 Fractions


HGB A1aHGB A1bHGB A1cHGB A1c is predominant fraction 3-6% is normal


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.


Hematacrit definition


Ratio of RBC volume to total blood volume.


Calculation of HCT


RBC Volume / Total Volume x 100%


Calculation of Hgb from HCT


1/3 HCT is Hemoglobin


Hematocrit Increase


Dehydration and ShockBurnsPolycythemiaAltitude (nonpathological)


Pathological decrease of Hct


AnemiaHemorrhagePregnancyEdemaCirrhosis


Nonpathological Decrease of HCT


Surgery with Blood LossBlood DonationOver 50 years of ageAltitudeRecumbent PatientAfter MealsLong Distance Runners


Age affecting Values


Higher in NewbornsLower in kids 1-12lower over age 50Lower in Femaleshigher in males


Normal HCT Ranges


Men 42 +/- 6Female 47 +/- 8Surgery 30Nonsurgery 24Panic Value 11


Collection Method for HCT


Heparinized Micro TubesMay collect in edta containerCentrifuge Stat


Centrifuge Microhematocrit.


3 minutes @ 12000 gMeasure within 10 minutes.Duplicate tests must agree within 1-2%Look for Hemolysis, Jaundice, Lypemia.


Trapped Plasma


Plasma that surrounds RBCs after spun


Buffy Coat


Layer in between RBCs and plasma composed of WBC and platelets.


Calculate RBC from MCV Values


HCT= RBC x MCV / 10


PCV


Packed Cell Volume


MCV


mean cell volume