MLS Heme lec 8
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| 4 common lab tests | ESR-inflammation
Hgb-anemia
Hct-anemia
Indices-cell morphology
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| What does ESR stand for | Erythrocyte sedimentation rate
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| ESR test is | Simple, non-specific screening test for inflammation
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| ESR test steps | 1. Anticoagulated blood is allowed to stand undisturbed for 1 hour
2. RBCs settle slowly,due to small mass, to bottom of the tube
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| Rouleaux | stacking of red blood cells
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| Rouleaux indicates | certain diseases increase rouleaux, increasing RBC mass and causing increased fall-out rate
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| Definition ESR | distance in mm that RBCs will fall in 1 hr in a vertical tube of defined length
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| Fall-out proportions | Directly: red cell mass
Inversely: plasma viscosity
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| Zeta | cloud of negative charges found on cell membrane
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| What weakens the zeta potential | Fibrinogen and other proteins by attracting positive ions close to the cell
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| Fibrinogen | Acute phase reactant
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| Weakened zeta potential allows | Rouleaux and fall-out
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| Increased RBC fall-out indicates | Increased fibrinogen
In vivo rouleaux of cells
Multiple myeloma increases immunoglobulin
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| Decreased RBC fall-out | Polycythemia
Sickle cells
Spherocytes
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| Normal RBC fall-out | Male: 0-20 mm/hr
Female & Children: 0-15 mm/hr
value related to red cell count
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| ESR Methods | Wintrobe
Wetergren
Automated
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| Westergren method | considered the universal reference method
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| Automated method | Shorter times, approximately 20 min
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| Technical factors affecting ESR results | Vertical slant
Temperature
Bubbles
Abnormal shapes
Won't rouleax
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| ESR Values | Cannot be "decreased" since zero is normal
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| Hemoglobin is the best measure of | anemia
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| Increased inflammatory conditions | Infections, especially bacterial
Auto-immune diseases
Neoplasms
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| Hemoglobin measurement | all but sulfhemoglobin with cyanmethemoglobin as a reference
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| Sulfhemoglobin can occur from | antibiotics or pesticides
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| Methemoglobin reacts with cyanide to create | Cyanmethemoglobin (HiCN)
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| Based on Beer's Law concentration is | Absorbance of HiCN is proportional to Hgb
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| Transmission absorbance | measured spectrophotometrically at 540nm
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| Hemoglobin Reference Range | Male: 12-16 g/dL
Female: 14-18 g/dL
Newborn: 22 g/dL
Children: 11-14 g/dL
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| Hct, PCV | Hematocrit
Packed cell volume
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| Hct expressed as | Percentage of whole volume RBC
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| Hct test | Manual method uses capillary tubes. Automated is % of whole blood after centrifugation
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| Manual Hct test | Capillary tube is filled with blood and centrifuged at 8000g (11,000-15,000 RPM) for five minutes. Omit buffy coat. Use special device to read % of RBC
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| Automated Hct | Not directly measured when automated instruments are used. Corrective calculation must be done
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| Indirect Hct calculation | RBC x MCV/10
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| Automated Hct disadvantage | In-vivo agglutination occurs, will affect Hct. RBC and MCV will be erroneous
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| Automated Hct advantage | No trapped plasma
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| When is manual Hct performed | Suspect spurious automated results or cannot get a tube of blood
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| Rule of 3 | Hct should be 3x Hgb, +/- 3%
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| Reference Range for Hct | Male: 42-52%
Female: 37-47%
Newborn is higher
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| RBC indices | Numerically describes cell morphology
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| MCV mean cell volume | Indicates size or volume of cell. Higher number, larger cell.
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| What can cause a falsely elevated MCV | Agglutination
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| Automated instruments measure MCV by | Size of pulse and derived from histogram
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| MCV calculation | (Hct/RBC) x 10=fL
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| MCV reference range | 80-100fL
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| MCV Determines | normocytes, macrocytes, and microcytes
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| MCH mean cell hemoglobin | average weight of hemoglobin, usually 1/3 MCV
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| MCH calculation | (Hgb/RBC) x 10= pg
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| MCH reference range | 28-32pg
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| MCH & MCHC values are | always calculated
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| MCH & MCHC value corresponds to | hypochromasia (decreased Hgb) or hyperchromasia (increased Hgb)
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| What can alter the value of the MCH | lipemic specimen or cold agglutinin
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| MCHC mean cell Hgb concentration | Average Hgb concentration of all red cells in sample, usually corresponds to MCH
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| MCHC Calculation | (Hgb/Hct) x 100 = value in %
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| MCHC Reference Range | 30-36%
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| Hypochromasia | decreased cellular hemoglobin concentration
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| Hyperchromasia | to much hemoglobin for size of the cell, observed in spherocytes or artifact
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| RBC Morphology: normocytic, normochromic | Conditions: normal, anemias, most hemoglobinopathies
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| RBC Morphology: Moderate anisocytosis, increased RDW:more variation in size | Conditions: sideroblastic anemia, transfusion, or treated anemia
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| RBC Morphology:Slight macrocytes, increased MCH ,right shift MCHC, increased MCV usually | Conditions: Liver disease
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| RBC Morphology: Moderate anisocytosis & moderate macrocytes, all markers elevated | Cnditions: Megaloblastic anemia (B12 & folate), reticulocytes & myelodysplasia
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| RBC Morphology: Moderate anisocytosis; moderate hypochromasia, all markers low | Conditions: Thalssemia
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| RBC Conditions: Moderate anisocytosis, slight microcytosis, slight hypochromasia. MCV,MCH,RDW increased | Conditions: Iron deficiency, sideroblastic anemia, lead poisoning
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| RBC Morphology: Moderate anisocytosis, moderate spherocytes. MCH, MCHC increased & MCV wider | Conditions: Hereditary spherocytosis & autoimmune hemolytic anemia (AIHA)
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