Which of the following can cause false-negative sickle solubility test results?
False-negative solubility test reactions may occur with inadequate quantities of blood from anemic patients (hemoglobin levels <8.0 g/dL); high concentration of Hb F or of phenothiazines may inhibit the sickle reaction;1 quantities of hemoglobin S too small to detect, as at birth or with transfusions of nonhemoglobin S …
Why is solubility test misleading in newborns?
Solubility tests are inappropriate, in part because high levels of fetal hemoglobin give false-negative results.
Can you get a false positive sickle cell test?
False-positive results can be obtained if nucleated red blood cells are present in the peripheral blood or the patient has marked hypergammaglobulinemia (such as in multiple myeloma).
What does a positive sickle cell solubility test mean?
Positive result: Indicates that the screening test detected the presence of Hemoglobin S or sickle hemoglobin, which may mean you carry the sickle cell trait.
What is sickle solubility?
A sickle cell solubility test is a quick test to screen for sickle cell disease or sickle trait. “Solubility” means how well a particular substance can dissolve in a liquid. In this case the substance is the hemoglobin molecule, the major protein in red blood cells, and the liquid is blood plasma.
Can sickle cell test wrong?
Iron deficiency or blood transfusions within the past 3 months can cause a false negative result. This means the person might have the abnormal hemoglobin for sickle cell, but these other factors are making their test results appear negative (normal).
What is hemoglobin solubility test?
Description. The Hemoglobin (Hb) Solubility Blood Test evaluates for the presence of the abnormal hemoglobin S (Hb S or Hgb S). Individuals with two copies of the Hb S gene (homozygous) have sickle cell anemia, also known as sickle cell disease.
How do you know if a baby is a Sickler?
If your baby has Hb SS, they will have a large number of red blood cells that are sickle or crescent shaped rather than donut-shaped. Clinical genetic testing for Hb SS is available and may be necessary to confirm the diagnosis.
What is a solubility test?
Solubility test is a type of test that is usually carried out to determine a compounds ability to dissolve in a solvent, which is usually some liquid. The test helps to find the polarity including the size of unknown compounds. It is also used to determine whether compounds are acidic or basic.
How is sickle solubility test done?
The test is done as follows: Blood is drawn into a tube that prevents the blood from clotting. Sodium dithionite or a similar chemical is then added to the blood. The sodium dithionite makes the red blood cells “lyse” or break open, releasing the hemoglobin from inside the red blood cells into the blood plasma.
What does a negative sickling test mean?
A sickle cell test looks only for the presence of hemoglobin S, which causes SCD. A negative test is normal. It means your hemoglobin is normal. A positive test result may mean you have sickle cell trait or SCD.
What causes a false positive solubility test for sickling?
False-positive solubility test for sickling may be due to polycythemic blood; interference by some forms of hyperglobulinemia; and a variety of abnormal hemoglobins, including I, Bart, C Georgetown, Alexandra, C Harlem, Porto Alegre, Memphis/S, C Ziguinchor, and S Travis. 1 Positive tests should be confirmed by hemoglobin fractionation.
What does it mean to have a false positive on a pregnancy test?
False negative test results can occur in many different medical tests, from tests for pregnancy , tuberculosis or Lyme disease to tests for the presence of drugs or alcohol in the body. Correspondingly, a false-positive test result indicates that a person has a specific disease or condition when the person actually does not have it.
When to test for solubility of hemoglobin?
Maximum levels are not reached until about six months of age. Solubility tests are unlikely to be reliably positive until after six months of age; therefore, this test should not be used for testing neonates or children younger than six months of age.
What happens if both ELISA test results are positive?
If the both ELISA test results are positive, a confirmatory test (using different laboratory techniques, such as a western blot or an immunofluorescence assay) is conducted. Both initial and confirmatory tests must have reactive, or positive, results in order for a person to be given a positive result.