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Introduction ⬇

Bart Hb is an unstable Hb with high oxygen affinity. When there is complete absence of production of the chain of Hb and deletion of all four globin genes, the disorder is known as Bart hydrops fetalis. Both parents of the affected infant have heterozygous thalassemia; they are almost all of Southeast Asian descent. Affected infants are either stillborn or die shortly after birth.

This test determines the percentage of the abnormal Bart Hb in cord blood and identifies alpha-thalassemia hemoglobinopathies.

Normal Findings ⬆ ⬇

Adults: none

Children: none

Newborns: <0.5% or <0.005 mass fraction of total Hb

Procedure ⬆ ⬇

  1. Obtain a sample of cord blood and perform Hb electrophoresis.

  2. Venous blood anticoagulated with EDTA or heparin can be used.

Clinical Implications ⬆ ⬇

Increased levels are associated with:

  1. Homozygous alpha-thalassemia (hydrops fetalis syndrome, which causes stillbirth)

  2. Hb H disease

  3. Alpha-thalassemia minor

Interventions ⬆

Pretest Patient Care

  1. Explain test purpose and procedure to parents.

  2. Obstetric complications may lead to significant morbidity and mortality for the mothers of these infants.

  3. Provide genetic counseling in a sensitive manner.

  4. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.

Posttest Patient Care

  1. Review test results and counsel the patient’s parents or legal guardians regarding abnormal findings; explain the need for possible follow-up testing and treatment.

  2. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.