The tissue typing laboratory carries out 3 tasks :

• To determine the HLA type of blood for both  donor and recipient by PCR.
• Lymphocyte cross-matching.
• HLA antibody screening and specificity

The complement-dependent lymphocytotoxicity (CDC) method has been the classical technique to detect human leukocyte antigen (HLA). Because of the drawbacks of CDC, such as low sensitivity and low resolution in characterizing antibody specificities, the more specific ELISA technology was introduced in the 1990s which utilizes solubilized HLA molecules instead of lymphocytes.

The Luminex® bead assay is a sensitive method for detection of HLA antibodies and represents the current highpoint in the evolution of HLA antibody detection assays. During the last 10 years, the introduction of the Luminex-based single antigen bead (L-SAB) technology, which uses recombinant single HLA molecules, allows detection and characterization of HLA antibodies at greater sensitivity than CDC and ELISA

CDC cross match found less sensitive than Luminex® cross match. There is no recommended “cut off” value for MFI positivity. It came positive when Luminex® mean fluorescence values (MFI) values were more than 5.000, but for a severe rejection some laboratories set values > 10,000.