Home
HelpTest ID FRAG Osmotic Fragility, Erythrocytes
Useful For
Evaluation of suspected hereditary spherocytosis associated hemolytic anemia
Confirming or detecting mild spherocytosis
Profile Information
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| FRAGO | Osmotic Fragility | No | Yes |
| SCTRL | Shipping Control Vial | No | Yes |
Method Name
Osmotic Lysis
Reporting Name
Osmotic Fragility, RBCSpecimen Type
ControlWhole Blood EDTA
Specimens must arrive within 72 hours of draw.
A whole blood EDTA specimen and a control specimen are required.
Forms: If not ordering electronically, complete, print, and send a Benign Hematology Test Request Form (T755) with the specimen (http://www.mayomedicallaboratories.com/it-mmfiles/benign-hematology-test-request-form.pdf)
Patient:
Container/Tube: Lavender top (EDTA)
Specimen Volume: 4 mL
Collection Instructions:
1. Immediately refrigerate specimen after draw. Refrigerate at 0 to 4° C. Do not freeze. Freezing causes sample lysis, and tests will not be performed on hemolyzed specimens.
2. Send specimen in original tube. Do not aliquot.
3. Rubber band patient specimen and control vial together. Control must accompany the patient sample at all times to ensure the reliability of testing results.
4. Be sure specimen and control are stored and transported together at refrigerate temperature, carefully following proper handling and shipping instructions.
Additional Information: Patient's age and sex are required.
Normal Shipping Control:
Specimen Type: Whole blood
Container/Tube: Lavender top (EDTA)
Specimen Volume: 4 mL
Collection Instructions:
1. Draw a control specimen from a normal (healthy), unrelated, nonsmoking person at the same time as the patient.
2. Label clearly on outermost label normal control.
3. Immediately refrigerate specimen after draw. Refrigerate at 0 to 4° C. Do not freeze. Freezing causes sample lysis, and tests will not be performed on hemolyzed specimens.
4. Send specimen in original tube. Do not aliquot.
5. Rubber band patient specimen and control vial together. Control must accompany the patient sample at all times to ensure the reliability of testing results.
Specimen Minimum Volume
2 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Control | Refrigerated | 72 hours |
| Whole Blood EDTA | Refrigerated | 72 hours |
Clinical Information
Spherocytes are osmotically fragile cells that rupture more easily in a hypotonic solution than do normal RBCs. Because they have a low surface area:volume ratio, they lyse at a higher osmolarity than do normal discocyte (RBCs). Cells that have a larger surface area:volume ratio, such as target cells or hypochromic cells are more resistant to lysing. After incubation, an increase in hemolysis is seen in spherocytes. Hereditary spherocytosis typically has greater number of spherocytes than other causes of spherocytosis. Therefore, the degree of lysis is usually more pronounced, but this is not always the case. Some rare disorders can also cause marked fragility and hereditary spherocytosis cases can display moderate fragility.
Reference Values
≥12 months:
0.50 g/dL NaCl (unincubated): 3-53% hemolysis
0.60 g/dL NaCl (incubated): 14-74% hemolysis
0.65 g/dL NaCl (incubated): 4-40% hemolysis
0.75 g/dL NaCl (incubated): 1-11% hemolysis
Reference values have not been established for patients who are <12 months of age.
Cautions
Spherocytosis of any cause will result in increased osmotic fragility. Infrequently, other congenital hemolytic disorders may also be associated with positive results, as in patients with congenital nonspherocytic hemolytic anemia due to RBC enzyme deficiencies.
Patients with an immunohemolytic anemia, or who have recently received a blood transfusion may also have increased RBC lysis.
The shipping control specimen is required to adequately
interpret these cases, as temperature extremes can increase the
fragility of the specimen and cause false-positive results.
Resulting Cautions:
Osmotic fragility results will be reported if the shipping control is normal.
If the shipping control is abnormal and the osmotic fragility results on the patient are within normal range, the results will be reported; however, a comment will be added to the report indicating that the shipping control was not entirely satisfactory.
The test will be cancelled if the patient specimen and shipping control are both abnormal.
Day(s) Performed
Monday through Saturday
Report Available
2 daysPerforming Laboratory
Mayo Medical Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.CPT Code Information
85557