Introduction: Testing for Rh system is performed as a routine test in blood banks. Rh system is one of the most polymorphic blood group systems. Rh positivity and negativity refers to presence or absence of D antigen on the red cell surface because it is most immunogenic and clinically important. Sometimes categorization of a person into definite D positive or D negative becomes difficult because variable expression of D antigen can occur. This is known as weak D/ partial D. Clinically weak D or partial D are of concern because serologically, it presents as Rh negative but for recipients they behave as Rh positive with possible risk of alloimmunization. Therefore, present study was undertaken with an aim to know the frequency of weak D antigen among donors and recipients presenting   to our blood bank.

Material and Method: This was a one year observational hospital based study including recipients and donors. All patients were tested for Rh-D factor by commercially available monoclonal anti-D sera. The individuals who were found negative with anti-D were further investigated for weak D antigen by using indirect antiglobulin test using AHG sera by tube technique.

Results: During study period a total of 37,943 blood samples, including donors and recipients were tested for Rh antigen. Out of total samples tested 1,094 (2.88 %) were Rh negative and remaining (97.12%) were Rh positive. Antiglobulin test yielded positive results for Du in 6 persons (0.54% of Rh negative and 0.015% of all subjects).

Conclusion: Present study concluded that D^U prevalence among individuals presenting at our blood bank is 0.54%.  we recommend that serologic testing of all D negative patients and donors should proceed to antiglobulin phase for identification of weak D positive donors. 

Keywords: D^u, Weak Rh, Rh Negative.

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