Rhogam is given to RH negative or D negative pregnant and post pregnant females Rhogam. The RH grouping consist of D, C, c, E, e. antigen typing determines if patient is RH positive or negative.
Rh positive patients who are “weak D positive” may receive Rhogam. Reduced expression of D antigen occurs in an estimated 0.2%–1% of Caucasians. Weak D testing is performed when initial agglutination grading is 2 or less. D red cell antigens that react with anti-D only after extended AHG testing are called weak D. Weak D expression primarily results from single point mutations in RHD. Weak D positive patients are are known in some cases to produce anti D after pregnancy or blood transfusion.
So, in most cases the pathologist will order the Rhogam for a Weak D positive patient to prevent the formation of anti D.
Recently the AABB, the American Association of Blood Banks, has recommended the implementation of molecular testing for weak D obstetrician patients as a means to determine the usage of Rhogam. This molecular testing focuses on identifying the weak D antigen, helping medical professionals make informed decisions regarding the administration of Rhogam. It is worth noting that certain hospitals have chosen to adopt protocols that dictate the mandatory “Weak D testing” for all RH negative patients, ensuring comprehensive care for this specific population. By employing these protocols, healthcare providers aim to mitigate the potential risks associated with Rh incompatibility during gestation. Overall, these initiatives enhance patient safety and promote efficient healthcare practices in the field of obstetrics.