Osmotic fragility
(OST)

sample type:

whole blood (lithium heparin)

uses:

The osmotic fragility test may also be used to help confirm if thalassemia or spherocytosis is the cause of anemia. By measure RBCs resistance to hemolysis when exposed to a series of increasingly dilute saline solution

Precaution:

• Is recommended that testing should be done within two hours after collection. If the test cannot be performed within this time frame, the blood should be refrigerated. Osmotic fragility testing can be adversely affected by temperature and pH. Hemolyzed sample should not be used.

• Must be sampling on lithium heparin

• Knowing type of test Immediate test or 24-hour incubation

interfering factors:

Osmotic fragility of red cells is increased by the use of mefenamic acid. The use of this analgesic induces hemolytic anemia. Study of osmotic fragility of RBCs of control and test was observed following administration of 7.1 mg, 10.5 mg and 14 mg/day mefenamic acid to each lizard. Increased osmotic fragility was observed with increase in the amount of dose on day 6 and day 12. The test is incubated at 37°C for 24 hours, at which time the test is positive for hereditary spherocytosis

Pre analytical error:

1) Specimens other than serum; improper labeling; samples not stored properly; samples older than stability limits; gross hemolysis; gross lipemia.

2) Take sample type different from that recommended in this test and analysis it in laboratory.

3) Not to put the name of the patient or error when putting the code of patient on the tube when sampling.

4) sample is contaminated from technicians, this sample will be cultured in microbiology LAB.

Corrective action:

1) refused the sample and ordered another sample.

2) The sample should be rejected and order another sample.

3) anther sample request and should attention at next time.

4) The sample must be rejected, and another sample will be requested.

Post analytical error:

1) Sharing the results of patients or writing the result incorrectly.

2) write a wrong Patient name in patient report.

Corrective action:

1) communicate with patient then delivered him the correct results and we apologize for this mistake.

2) the report is not delivered to the patient and the error must be discovered.

Reference range:

• Immediate test: Hemolysis begins at 0.5% NaCl Hemolysis complete at 0.3% NaCl

• 24-hour incubation: Hemolysis begins at 0.7% NaCl Hemolysis complete at 0.4% NaCl