CPT® Code 88245

1. Indications

The procedure described by CPT® Code 88245 is indicated for the evaluation of breakage syndromes, which may present with various symptoms and conditions. The following are specific indications for performing this chromosome analysis:

• Breakage Syndromes The analysis is performed to identify genetic conditions characterized by increased chromosome breakage, such as ataxia telangiectasia, Fanconi anemia, and fragile X syndrome.
• Increased Sister Chromatid Exchange The test is indicated when there is a suspicion of elevated SCE due to exposure to certain chemicals, infectious agents, or physiological disorders.

2. Procedure

The procedure for CPT® Code 88245 involves several critical steps to ensure accurate analysis of Sister Chromatid Exchange (SCE). The following outlines the procedural steps:

• Step 1: Sample Collection Peripheral blood is collected from the patient, which serves as the source of lymphocytes for the analysis.
• Step 2: Cell Culture The collected lymphocytes are cultured in a separate, reportable procedure. During this phase, the cells are stimulated to divide using a nonspecific antigen, such as phytohemagglutinin, which promotes mitotic activity.
• Step 3: Spindle Inhibition A spindle inhibitor is added to the culture to halt the cells in metaphase after a second mitotic division. This step is crucial for ensuring that a sufficient number of mitotic cells are available for analysis.
• Step 4: BrdU Incorporation Bromo-deoxy-uridine (BrdU) is introduced into the culture medium for the duration of two complete cell cycles. This compound allows for differential staining of the chromatids, facilitating the identification of exchanges.
• Step 5: Staining and Analysis After the culture period, the cells are stained using Giemsa staining. Chromatids that incorporate only one strand of DNA will exhibit dark staining, while those with two strands will stain less darkly. The presence of dark staining on one arm of the chromosome indicates an exchange, resulting in the formation of harlequin chromosomes.

3. Post-Procedure

After the completion of the Sister Chromatid Exchange analysis, the results are evaluated to determine the presence of chromosomal exchanges indicative of breakage syndromes. The findings may require further investigation or additional testing, depending on the results. Patients may be advised on follow-up consultations to discuss the implications of the findings and any necessary next steps in their care. It is essential to document the results accurately and communicate them to the referring physician for appropriate management of the patient's condition.