In contrast to WAIHA and DHTRs, the eluate is nonreactive, because the reagent RBCs lack the drug required for the antibody to bind.
The negative eluate result was not compatible with WAIHA or a DHTR.
The main differential diagnosis for immune-mediated hemolysis includes WAIHA, DHTRs, cold agglutinin disease, and DIIHA.
 Nonstandard abbreviations: DAT, direct antiglobulin test; RBC, red blood cell; LDH, lactate dehydrogenase; WAIHA, warm autoimmune hemolytic anemia; DHTR, delayed hemolytic transfusion reaction; DIIHA, drug-induced immune hemolytic anemia.
Reactivity that demonstrates pan agglutination is typical of WAIHA. Cold AIHA and drug-induced anemias will usually be non-reactive.
When the IAT and eluate are all demonstrating panreactivity, this is usually conclusive for a WAIHA. But, in order to provide RBCs for transfusion, it is important to identify any alloantibodies present.
It is important to note that the decreased red cell survival in patients with WAIHA affects all cells, donor and recipient, and therefore, some hospitals may perform the technique on recently transfused patients after a 90 day period.
An option employed by some hospitals involves the initial phenotyping of all patients that present with WAIHA. The phenotype can be obtained utilizing immediate spin or room temperature incubation anti-sera, as long as an auto-control is performed in tandem.
Taking the concept of initial phenotyping further, the idea of utilizing prophylactic antigen-matched (PAM) donor blood for on-going transfusion therapy of WAIHA patients is definitely worth further investigation.
Apellis is also testing APL-2 in a Phase 2 open-label trial assessing the safety, tolerability, efficacy, and PK of multiple subcutaneous (SC) doses of APL-2 administered daily in patients with wAIHA