Osmotic Fragility, Erythrocyte
Test Mnemonic
OSMFER
CPT Codes
- 85555 - QTY (1)
Performing Laboratory
ARUP
Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 5 mL | Whole blood | EDTA (Lavender) | Refrigerated | Submit 2 unfixed, air-dried, and unstained smears AND 5 mL whole blood. Specimens should be refrigerated within 30 minutes after collection. Place both slides and whole blood specimens in an osmotic fragility transport kit (ARUP supply #53821). |
Alternate Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 5 mL | Whole blood | Sodium or Lithium heparin (Green) | Refrigerated | Submit 2 unfixed, air-dried, and unstained smears AND 5 mL whole blood. Specimens should be refrigerated within 30 minutes after collection. Place both slides and whole blood specimens in an osmotic fragility transport kit (ARUP supply #53821). |
Minimum Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 1 mL | Whole blood | ||||
| 2 slides | Minimum of 2 smears made from the blood submitted |
Stability
| Environmental Condition | Description |
|---|---|
| Ambient | Unacceptable |
| Refrigerated | 72 hours |
| Frozen | Unacceptable |
Days Performed
Mon - Fri
Turnaround Time
2 - 6 days
Methodology
| Name | Description |
|---|---|
| Spectrophotometry (S) |
Reference Range
Special Info
Grossly hemolyzed specimens are unacceptable.
Clinical Info
Functional testing of red blood cell sensitivity to osmotic stress; do not use to distinguish between spherocytes in hereditary spherocytosis and acquired autoimmune hemolytic anemia. For patients with acute hemolysis, a normal red cell osmotic fragility test result cannot exclude an osmotic fragility abnormality since the osmotically labile cells may be hemolyzed and not present. Recommend testing during a state of prolonged homeostasis with stable hematocrit.