Evaluation of suspected hereditary spherocytosis associated hemolytic anemia
Confirming or detecting mild spherocytosis
Test Id | Reporting Name | Available Separately | Always Performed |
---|---|---|---|
FRAGO | Osmotic Fragility | No | Yes |
SCTRL | Shipping Control Vial | No | Yes |
Osmotic Lysis
FRAGILITY, OSMOTIC (RBC)
RBC Fragility, Erythrocytes
Red Cell Fragility
Control
Whole Blood EDTA
Specimens must arrive within 72 hours of collection.
Patient's age and sex are required.
Both a whole blood EDTA specimen and a control specimen are required as temperature extremes can increase the fragility of the specimen and cause false-positive results.
Patient:
Container/Tube: Lavender top (EDTA)
Specimen Volume: 4 mL
Collection Instructions:
1. Immediately refrigerate specimen after collection. Refrigerate at 0 to 4 degrees 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 refrigerated temperature, carefully following proper handling and shipping instructions.
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. Handwrite "normal control" clearly on the outermost label.
3. Immediately refrigerate specimen after collection. Refrigerate at 0 to 4 degrees 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.
If not ordering electronically, complete, print, and send a Benign Hematology Test Request (T755) with the specimen.
2 mL
Gross hemolysis | Reject |
Clotted blood | Reject |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Control | Refrigerated (preferred) | 72 hours | PURPLE OR PINK TOP/EDTA |
Whole Blood EDTA | Refrigerated (preferred) | 72 hours |
Evaluation of suspected hereditary spherocytosis associated hemolytic anemia
Confirming or detecting mild spherocytosis
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.
> or =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.
An interpretive report will be provided.
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.
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.
Palek J, Jarolin P: Hereditary spherocytosis. In Hematology.
Specimens for erythrocyte osmotic fragility tests are anticoagulated
Monday through Saturday
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 US Food and Drug Administration.
85557
Test Id | Test Order Name |
Order LOINC Value
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.
|
---|---|---|
FRAG | Osmotic Fragility, RBC | 98904-6 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
9064 | Osmotic Fragility, RBC | 34964-7 |
3306 | Osmotic Fragility, 0.50 g/dL NaCl | 23915-2 |
3307 | Osmotic Fragility, 0.60 g/dL NaCl | 23918-6 |
3308 | Osmotic Fragility, 0.65 g/dL NaCl | 23920-2 |
3309 | Osmotic Fragility, 0.75 g/dL NaCl | 23921-0 |
3310 | Osmotic Fragility Comment | 59466-3 |
SCTRL | Shipping Control Vial | 40431-9 |