Is eplet matching testing done through blood sampling or cheek swab?

Eplet Matching Testing: Blood Sample Collection Method

Eplet matching testing for transplantation is performed using blood samples, not cheek swabs. 1

Sample Collection Requirements

Blood Collection for HLA Typing and Eplet Analysis

• Blood sample type: EDTA blood tubes are used for DNA extraction and HLA genotyping 1
• Volume needed: Typically 5mL of blood in an EDTA tube is sufficient 1
• Processing timeframe: Blood should ideally be processed within 3 hours after collection for optimal results, though it can be stored for up to 24 hours in oscillating trays at appropriate temperatures 1

Blood Collection for Antibody Testing

• Sample type: Serum samples (not EDTA plasma) must be used for antibody detection 1
• Important caveat: EDTA plasma significantly reduces the sensitivity of antibody detection assays and should NOT be used for alloantibody investigations 1

Testing Workflow

1. DNA extraction from blood samples for HLA genotyping

2. High-resolution HLA typing using techniques such as:

   • Next-generation sequencing (NGS)
   • Real-time PCR
   • Sequence-specific primer (SSP) techniques
   • Restriction fragment length polymorphism (RFLP) 1

3. Eplet analysis using specialized software that:

   • Identifies amino acid polymorphisms between donor and recipient HLA molecules
   • Calculates eplet mismatches that may trigger antibody responses 2, 3

Clinical Significance

• Eplet mismatch analysis provides more precise prediction of immunological risk than traditional HLA matching 3, 4
• Higher eplet mismatches correlate with:
  • Increased risk of donor-specific antibody (DSA) formation 5
  • Higher rates of rejection 3
  • Reduced graft survival 3

Important Considerations

• Software limitations: Different eplet analysis programs (like HLAMatchmaker vs. Fusion MatchMaker) can give discordant results 6
• High-resolution typing requirement: Accurate eplet analysis requires high-resolution HLA typing; anything less requires imputation of HLA types 2
• Reference sample: When testing for potential transplant recipients, a blood sample from the recipient is required, and ideally from the donor as well 1
• Constitutional DNA: Blood samples provide a simple source for extraction of matched constitutional DNA from peripheral leukocytes, which is important for distinguishing somatic from germline genetic variants 1

Quality Control Measures

• Proper patient identification is crucial prior to blood collection 7
• Blood samples must be labeled at the patient's side with appropriate identifiers 7
• For antibody testing, serum samples should be used rather than EDTA plasma to maintain assay sensitivity 1

Eplet matching is increasingly recognized as an important tool for predicting transplant outcomes, but the technology is still evolving and requires standardized approaches to sample collection and analysis.