Allele Code Lists

Allele Code Update to Version 3 WHO Nomenclature

The alleles contained in the numeric and alphabetic allele code lists below contain alleles up through the most recent version of the IMGT HLA Database. The most recent version of the IMGT HLA Database can be found at: http://www.ebi.ac.uk/imgt/hla/

The NMDP uses allele codes to facilitate the reporting of HLA alleles. Ideally, allele codes narrow the list of alleles that must be considered at a given locus by eliminating some possibilities. (For example: a report of DRB1*01:AD means that the typing is either DRB1*01:01 or DRB1*01:0, but not DRB1*01:02 or DRB1*01:03.)

The allele codes allow typing laboratories to provide the maximum amount of information to transplant centers within the design constraints of search reports and the NMDP Registry. The NMDP allele code lists are used by laboratories, transplant center coordinators and other NMDP Network staff who work with donor and recipient HLA typings.

Instructions for Using the Allele Code Lists:

ANNOUNCEMENT :
               Starting July 8^th, 2019, these links will no longer be available on this site. Please refer to https://hml.nmdp.org/MacUI/ .  Any questions please contact: new-allelecodes@nmdp.org. 

There are two versions of the allele code list.

1. Sorted numerically
   This list has two sections which are sorted separately:
• Generic codes for multiple allele designations
  This section lists codes that can be used with any allele group or locus (as appropriate).
• Allele specific codes for allele combinations that cross serologic groups and for combinations that contain null alleles
  Allele specific codes are used for combinations that cannot be represented by generic codes. This includes combinations that cross serologic groups (DRB3*01:01/02:02 = 01TP) and combinations that include null alleles (A*24:02/24:09N = 24:AMG, not 24:BH).
2. Sorted alphabetically
   Consists of one list of all codes listed in alphabetical order. The three-letter codes are found at the end of the two-letter codes. Four-letter codes follow the three-letter codes.
   

Laboratories:

The allele code used for reporting an HLA typing to the NMDP must fit the allele combination EXACTLY. Allele codes can be found, or the activation status of an existing allele code can be checked, by using the MAC Ul tool. With this tool you enter the allele combination, and search for an allele code. If one exists, it will be displayed on the screen. If no code exists for the allele combination entered, Click encode which will create a code for you in the Encode/Lockup Result box. Any questions should be emailed to new-allelecodes@nmdp.org

How allele codes are made:

Allele codes are assigned as requests are submitted to the MAC Ul code are assigned primarily to allele combinations which represent a single serologic equivalent group. There are some codes which can be used with several loci and several allele families, these are called "generic" codes. Allele combinations that contain an expression character (e.g., N = null, S = soluble, L = low expression), or which cross serologic families (e.g., DRB3*01:01/01:02/02:03/02:06) are called "allele specific" codes and can only be used with the locus and allele family that were used when it was initially created.

How to use the allele codes:

Each allele combination is assigned a distinct allele code. When searching for an allele code using the MAC Ul Tool, the complete allele combination must be entered. If there are 30 possible alleles in the combination, DO NOT enter just the first two or three alleles and expect to get the correct allele code for the full allele combination. Shortening the list will result in a code which does not represent the combination obtained by laboratory analysis. DO NOT use the "best fit" for an allele combination, or a code that is close to the desired code. Additionally, when looking up an allele code, "ADEM", for example, DO NOT enter just "AD" and expect to get the complete allele string. ADEM = 03/07/08/10/13/26/30/32 and AD = 01/04. Finally, do not substitute generic alleles for those which contain an expression character. A*01:AD (01:01/01:04) cannot be used to represent A*01:04N. The correct code would be A*01:CRY (01:01/01:04N).