Which of the following is a common clinical manifestation of immunodeficiency disorders?

Explanation: The correct answer is a. Complete blood count (CBC) with differential. A CBC with differential is a standard diagnostic test used to assess the levels of different blood cells, including white blood cells, which are crucial for the immune system. Abnormalities in the white blood cell count and differential can indicate potential immunodeficiency.

Incorrect choices:

b. A chest X-ray is not a specific diagnostic test for immunodeficiency disorders. It is typically used to assess the condition of the lungs and chest organs.

c. An electrocardiogram (ECG) is a test used to assess the electrical activity of the heart and is not related to the diagnosis of immunodeficiency disorders.

d. A urinalysis is a test used to assess the urine for various abnormalities and is not specific to diagnosing immunodeficiency disorders.

Explanation: The correct answer is a. Severe combined immunodeficiency (SCID). SCID is a severe and rare primary immunodeficiency disorder characterized by the absence or severe impairment of both T and B cells, leading to a profound deficiency in cellular and humoral immunity.

Incorrect choices:

b. X-linked agammaglobulinemia (XLA) primarily affects B-cell function, resulting in a lack of mature B cells and low levels of immunoglobulins, but does not typically involve T-cell deficiency.

c. Wiskott-Aldrich syndrome affects platelet function and immune system regulation, but it is not characterized by a deficiency of both T and B cells.

d. Common variable immunodeficiency (CVID) is characterized by reduced levels of immunoglobulins, particularly IgG and IgA, but it does not typically lead to a complete deficiency of both T and B cells.