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Lab Dept:
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Hematology
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Test Name:
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OSMOTIC FRAGILITY
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General Information
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Lab Order Codes:
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OSFM
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Synonyms:
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RBC Fragility; Erythrocyte Fragility; Incubated Osmotic Fragility
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CPT Codes:
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85557 – Osmotic fragility, RBC; incubated
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Test Includes:
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Percent hemolysis of red blood cells for unincubated specimens placed in 0.50 g/dL concentration of NaCl and incubated specimens (37°C for 24 hours) when tested in NaCl concentrations of 0.60, 0.65 and 0.75 g/dL.
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Logistics
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Test Indications:
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Useful for suspected hereditary spherocytic hemolytic anemia.
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Lab Testing Sections:
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Hematology - Sendouts
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Referred to:
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Mayo Medical Laboratories (MML Test# 9064)
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Phone Numbers:
Minneapolis:
Saint Paul:
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612-813-6280
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651-220-6550
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Test Availability:
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Daily, 24 hours
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Turnaround Time:
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2 – 4 days (not reported on Saturday or Sunday)
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Special Instructions:
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Indicate patient’s date of birth on request form. Specimen must arrive at reference lab within 72 hours of draw.
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Specimen
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Specimen Type:
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Whole blood
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Container:
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Lavender top (EDTA) tube
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Draw Volume:
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5 mL (Minimum: 2 mL) blood
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Processed Volume:
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Same as Draw Volume
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Collection:
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A trauma-free blood collection required
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Special Processing:
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Send 5 mL EDTA blood refrigerated. Specimen should remain in original collection container. Do not transfer blood to another tube. Do not centrifuge.
Also, send a 5 mL fresh EDTA whole blood specimen from a normal, untreated person at the same time, refrigerate and Label as normal control, indicate sex of the person from whom the control was drawn on the specimen label.
Do Not freeze.
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Patient Preparation:
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None
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Sample Rejection:
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Clotted, frozen, mislabeled or unlabeled specimen
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Interpretive
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Reference Range:
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0.50 g/dL NaCl (unincubated)
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Males: 0.0 – 47.8% hemolysis
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Females: 0.0 – 31.1% hemolysis
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0.60 g/dL NaCl (incubated)
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Males: 18.7 – 67.4% hemolysis
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Females: 10.9 – 65.5% hemolysis
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0.65 g/dL NaCl (incubated)
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Males: 4.4 – 36.6% hemolysis
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Females: 0.2 – 39.3% hemolysis
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0.75 g/dL NaCl (incubated)
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Males: 0.8 – 9.1% hemolysis
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Females: 0.0 – 10.9% hemolysis
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Critical Values:
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None
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Limitations:
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Infrequently, other hemolytic disorders may be associated with positive results, as in patients with congenital nonspherocytic hemolytic anemia due to G-6-PD or pyruvate kinase deficiency.
Patients with an immunohemolytic anemia, or who have recently received a blood transfusion may also have increased RBC lysis.
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Methodology:
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Osmotic Lysis
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Contraindications:
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Recent transfusion
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References:
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Mayo Medical Laboratory Web Page May 2011
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Updates:
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11/6/2006: Updated reference ranges.
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