A 6-year-old boy presents with severe abdominal and chest pain. What is the most appropriate next diagnostic step for possible sickle cell disease?

In the case of a 6-year-old boy presenting with severe abdominal and chest pain, the most appropriate next diagnostic step for possible sickle cell disease is hemoglobin electrophoresis. This test is essential for diagnosing sickle cell disease as it specifically measures the different types of hemoglobin present in the blood.

Sickle cell disease is caused by a mutation in the β-globin gene, leading to the production of abnormal hemoglobin known as hemoglobin S. During hemoglobin electrophoresis, various types of hemoglobin, including fetal hemoglobin (HbF), normal adult hemoglobin (HbA), and the sickle hemoglobin (HbS) can be separated and quantified. This test not only confirms the presence of sickle cell disease but can also illustrate the ratio of different hemoglobin types, which is critical in determining the patient's condition and potential complications.

Other diagnostic options, while potentially relevant in certain scenarios, do not specifically address the suspicion of sickle cell disease. For example, a complete blood count can show anemia or leukocytosis but lacks specificity for sickle cell diagnosis. A chest X-ray may be useful if there is a concern for pneumonia or other thoracic issues but does not aid in diagnosing sickle cell disease directly