OSMOTIC FRAGILITY ERYTHROCYTES

General Information

HLAB/HOL Code: RCF
UPHSM LIS Test #: 022944
Schedule:
Testing Time: 2-5 Days
Testing Lab: Mayo

Specimen Info
Only 1 specimen type required, unless otherwise specified

Volume: 5.0 mL
Temperature: Refrigerate
Tube Type: Whole Blood (EDTA)
Collection Info:
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.

Specimen Acceptability

REJECT DUE TO:
Gross hemolysis: Reject
Clotted blood: Reject

Methods

Osmotic Lysis

Clinical Utilities

Spherocytes are osmotically fragile cells that rupture more easily in a hypotonic solution than do normal red blood cells. 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 hereditary spherocytosis.  The test is helpful in confirming or detecting mild spherocytosis.  Infrequently, other hemolytic disorders may also be associated with positive tests, as in patients with congenital nonspherocytic hemolytic anemia due to glucose-6-phosphate dehydrogenase (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.

CPT Codes

85557

* The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding
is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.

Reference Range

> 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.