iecDtr lngtnuoilbAi = rDtcei omoCbs sTte

Dseettc idobeiasnt nbdou rytcedli ot .sRBC eyloHisms stom lyeilk ude to ositemghn ni teh seafrdutns oodlb to(n reus wyh it ktoo 4 wseke hnew eyTp 2 HS si pdsusepo to be creikqu btu ).we/

I think this is delayed hemolytic transfusion reaction (which is why it took 4 weeks and she is not exhibiting signs and symptoms of shock).

From AMBOSS:

Pathomechanism: Occurs in patients who were previously sensitized to specific RBC antigens during transfusions, pregnancy, or transplantations. Re-exposure to the antigens results in a rapid increase in antibodies that bind to donor RBCs and cause extravascular hemolysis

Clinical features: Onset days or weeks after transfusion. Fever, jaundice, anemia, dark urine

Diagnostics: Antibody testing to prevent future reactions

Treatment: No acute therapy required

Regardless of whether it is acute or delayed hemolytic, they are both diagnosed with "direct antiglobulin test"