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10 Cards in this Set
- Front
- Back
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Explain the principle of the test method
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- Fresh whole blood mixed with stain
- Retics counted microscopically - Reported as % of total RBCs - In student lab, use manual method |
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Briefly describe the performance of the test via manual method
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Stain options
- New methylene blue - Brilliant cresyl blue - Precipitates residual RNA in ribo Imparts blue -green color to RBCs Fine, granular or linear inclusions = RNA Limitations to manual method - Counting error = 25% - Inefficient |
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State reference intervals and interpret patient results
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- Manual reference interval = 0.8-2.0%
- May be separate ref interval for males and females - Automated reference interval = 0.5 - 2.7% - Measures effective erythropoiesis , RBC production by BM - Increased in Increased rate of erythropoiesis Decreased # mature cells in PB Early releases of "STRESS" or "SHIFT" retics Example: recovery in BM transplants, chemotherapy, Treated anemia -Decreased in Ineffective erythropoiesis Decreased erythropoiesis Some types of anemia |
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Retic Calculation
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Convert to reporting units (%)
- Actual count per 1000 RBCs - Therefore divide by 10 Correct for anemia (decrease in number of mature RBCs) Corrected retic ct = % retics x (HCT/45) Correct for presence of "shift retics" - Retics which should have remained in marrow - Get released early due to incr need for RBCs. - Called "retic production index (RPI)" - Divide corrected retic by reticulocyte maturation time Absolute retic count - Multiply total RBC count by % retics (convert to decimal) - Report as #x10^6 / uL |
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ESR
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Principle
- Fill calibrated tube with fresh whole blood Dilute with NaCl for Westerngen method NOt diluted = Wintrobe method Automated methods available - Leave in vertical position for 1 hr - Note level to which RBCs fall ESR function of -Cell size & shape -Plasma viscosity/ proteins/ rouleaux -HCT level - Physical factors - can control for this |
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ESR reference ranges
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Female: 0-30mm/hr
Male: 0-20mm/hr |
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ESR clinical significance
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- Increased in inflammation
- Nonspecific - Replaced by CRP test which is quicker, more specific. |
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RBC Indices
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MCV
- HCT x 10/RBC - Reporting unit= fL MCH - HGB x 10/RBC - Reporting unit =pg MCHC - HGB x100/HCT - Reporting unti = g/dL or % |
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Significance of RBC indices
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MCV
- Average size RBCs - Corresponds to RBC size (diameter) on smears MCH - Average mass of HGB in RBC - Corresponds to RBC size - Bigger cells contain more HGB MCHC - Concentration of HGB in average cell - Corresponds to size of zone of central pallor on smear - A "pale" cell with large zone of central pallor has low MCHC |
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Indices Reference Ranges
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MCV: 80-100 fL
MCH: 26-34 pg MCHC: 31-37 g/dL or % |
