Name of the Procedure:

Comparative Analysis Using Short Tandem Repeat (STR) Markers; Patient and Comparative Specimen (e.g., Pre-transplant Recipient and Donor Germline Testing, Post-transplant Non-hematopoietic Recipient Germline Sample)

Summary

This procedure involves comparing DNA samples using Short Tandem Repeat (STR) markers to check for genetic similarities and differences. It is commonly used in transplant patients to match donor and recipient DNA or to verify patient identity by analyzing buccal swabs or other germline tissue samples.

Purpose

The primary purpose of the STR analysis is to ensure compatibility between donor and recipient in transplant scenarios and to confirm the identity of tissue samples pre- and post-transplant. It helps in minimizing the risk of transplant rejection and in monitoring the success of the transplant.

Indications

• Pre-transplant compatibility testing between recipient and donor.
• Post-transplant verification of patient identity in non-hematopoietic tissues.
• Ensuring genetic matches to reduce the risk of graft-versus-host disease (GVHD).

Preparation

• No specific preparation such as fasting is typically required.
• Patients may be instructed to avoid eating or drinking 30 minutes prior to buccal swab collection.
• A thorough medical history and prior genetic tests may be reviewed.

Procedure Description

1. Obtain samples (buccal swab or other germline tissue) from both patient and donor.
2. Extract DNA from collected samples.
3. Amplify specific STR regions in DNA using Polymerase Chain Reaction (PCR).
4. Analyze PCR products using capillary electrophoresis to detect STR markers.
5. Compare STR profiles of patient and comparative samples for genetic similarities or mismatches.

Tools and Equipment:

• Buccal swabs or other tissue collection tools
• DNA extraction kits
• PCR machine
• Capillary electrophoresis equipment

No anesthesia or sedation is typically required.

Duration

The entire procedure, from sample collection to analysis, typically takes 2-5 days, with the actual sample collection lasting only a few minutes.

Setting

Sample collection can be performed in a hospital, outpatient clinic, or clinical laboratory. The DNA analysis is conducted in a specialized genetics lab.

Personnel

• Clinical technician or nurse for sample collection
• Geneticist or laboratory technician for sample processing and analysis

Risks and Complications

• Very minimal risks associated with buccal swab collection, such as minor discomfort.
• Rare risk of sample contamination, which can be mitigated by following strict procedures.

Benefits

• Accurate compatibility testing helps ensure successful transplant outcomes.
• Quick and non-invasive sample collection.
• Early identification of potential transplant complications.

Recovery

• No recovery period is needed; patients can resume normal activities immediately following sample collection.
• Follow-up may include further compatibility tests or monitoring transplant success.

Alternatives

• Other genetic testing methods such as Single Nucleotide Polymorphism (SNP) analysis.
• Traditional histocompatibility testing methods, although they might be less precise.

Patient Experience

During the sample collection, patients may experience brief discomfort or gagging with buccal swabs. Overall, the procedure is quick, and patients can expect minimal disruption to their daily routine. Pain management is generally unnecessary.