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خرید پکیج
تعداد آیتم قابل مشاهده باقیمانده : 3 مورد
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Our approach to prenatal/preconception screening for hemoglobinopathies

Our approach to prenatal/preconception screening for hemoglobinopathies
Whether screening for hemoglobinopathy should be performed universally or targeted to populations at increased risk is controversial. Given the increasingly diverse ethnic and geographic distribution of hemoglobinopathy genotypes in the United States and elsewhere, risk assessment based on race and ethnic origin alone may not be reliable.

HPLC: high performance liquid chromatography; CBC: complete blood count; Hb: hemoglobin; MCV: mean corpuscular volume; MCH: mean corpuscular hemoglobin; IEF: isoelectric focusing.

* A ferritin level is obtained because iron deficiency can mask beta-thalassemia trait. The diagnosis heterozygous beta-thalassemia is based on an increased HbA2 level, but individuals with beta-thalassemia and concomitant iron deficiency can have a normal rather than increased HbA2 level. Therefore, in individuals with microcytosis and normal HbA2, testing must be repeated after iron repletion or DNA-based testing can be performed.

¶ These are the most common variants. If another hemoglobin variant is detected, consult a hematologist.

Δ The criteria for diagnosis of a hemoglobinopathy in the male partner are the same as the criteria for diagnosis in the female partner. Refer to UpToDate content for descriptions of counseling and fetal diagnosis.

◊ CBC and hemoglobin analysis will not identify alpha thalassemia silent carrier (loss of one of the four alpha globin genes), which can only be identified by DNA-based analysis. Therefore, DNA-based analysis should be considered in any patient with ethnic or familial risk factors for alpha thalassemia. Cost and the potential consequences of a missed diagnosis of HbH disease in offspring are factors in decision-making. If DNA-based testing shows the mother is not a carrier, no further testing is required. If DNA-based testing shows that the mother is a silent carrier, then paternal DNA-based testing should be performed. If the father has cis alpha thalassemia trait (loss of two alpha globin genes on the same chromosome), their child has a one in four chance of HbH disease (ie, loss of three of the four alpha globin genes). Newborns with HbH disease may have mild hemolytic anemia, often presenting with neonatal jaundice and mild anemia. Most do not require chronic transfusion but occasional transfusions may be needed. Iron overload due to increased iron absorption is also a significant issue.

§ Refer to UpToDate content for information on counseling and fetal diagnosis.
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