85505-6

LOINC code 85505-6 identifies "Presumptive Rh [Type] in Saliva (oral fluid) by Molecular genetics method". The presumptive (predicted) Rh factor for the D antigen (Rh positive or Rh negative) based on genetic analysis of the RHD gene. Hematopoietic stem cell transplant donor registries often collect samples from potential donors using buccal swabs or saliva (both described as "saliva" in the LOINC term) as part of enrolling them in the registry. Because these samples do not contain fresh intact red blood cells (RBCs) and traditional serological RhD blood group typing cannot be done, molecular typing is performed as part of the screening process to find an appropriate hematopoietic stem cell donor. Prior to transfusion or transplantation, the presumptive Rh factor result based on molecular typing must be confirmed using traditional serologic typing. This term was created for, but not limited in use to, the submitter's lab that performs sequence analysis of select exons in the RHD gene and predicts the RhD phenotype from the resulting DNA sequence.

This code measures Rh.presumptive in Saliva. It belongs to the BLDBK class in the LOINC classification.

LOINC (Logical Observation Identifiers Names and Codes) is a universal standard for identifying laboratory and clinical observations. It is maintained by the Regenstrief Institute and used worldwide for health data exchange.