Name of the Procedure:

Osmotic fragility test, RBC; incubated
Common name(s): RBC Fragility Test, Red Blood Cell Fragility Test
Technical/Medical term: Osmotic Fragility, Red Blood Cell (RBC); Incubated

Summary

The osmotic fragility test (RBC; incubated) evaluates the strength and stability of red blood cells (RBCs) when placed in varying concentrations of a saline solution. This test helps to diagnose certain conditions that affect the membrane of red blood cells.

Purpose

The osmotic fragility test is used to diagnose and monitor conditions that cause abnormal RBC membrane stability, such as hereditary spherocytosis or thalassemia. The goal is to identify the extent to which RBCs can withstand varying osmotic pressures before rupturing.

Indications

The test is indicated for patients with:

• Symptoms of hemolytic anemia like fatigue, jaundice, or pallor.
• Family history of hereditary spherocytosis or similar conditions.
• Unexplained anemia or splenomegaly.

Preparation

• No specific preparations such as fasting are generally required.
• Patients should inform their healthcare provider of any medications they are taking, as some drugs may affect red blood cell stability.
• A complete blood count (CBC) may be done before the procedure to assess overall hemoglobin levels.

Procedure Description

1. A blood sample is drawn from the patient.
2. The RBCs from the sample are isolated and placed in varying concentrations of sodium chloride (NaCl) solution to create hypotonic environments.
3. The test includes an incubation period of 24 hours to assess the RBC's fragility over time.
4. The extent of hemolysis (breaking of RBCs) is measured and compared to normal values.
5. The level of hemolysis indicates how fragile the red blood cells are under osmotic stress.

Duration

The initial blood draw takes about 10-15 minutes. The incubation period lasts for 24 hours, and follow-up assessments may take an additional 1-2 hours.

Setting

The test is performed in a laboratory setting, usually within a hospital or outpatient clinic.

Personnel

• Phlebotomist for blood sample collection.
• Laboratory technologists and technicians for test execution and analysis.
• A hematologist or a specialist who interprets the results.

Risks and Complications

• Minimal risk from blood draw, such as bruising or slight pain at the needle site.
• Rare instances of infection or phlebitis (inflammation of the vein).

Benefits

• Accurate diagnosis of conditions affecting RBC membrane stability.
• Helps in planning appropriate treatment strategies.
• Results are usually available within a few days to guide further medical decisions.

Recovery

• No significant recovery time needed.
• Patients can resume normal activities immediately after the blood draw.
• Follow-up appointments may be necessary for discussing results and further treatment.

Alternatives

• Eosin-5'-maleimide binding test (EMA) for diagnosing hereditary spherocytosis.
• Genetic testing for specific hereditary conditions.
• Peripheral blood smear and enzyme tests for more detailed evaluation of RBC morphology.

Patient Experience

• Patients may experience mild discomfort or pain during the blood draw.
• Generally, there is no pain during the incubation period since it is done in a lab.
• Pain management or comfort measures are not usually required.