Table 1.

Investigations in patients presenting with AIHA

Diagnostic tests	Indication for tests
Primary evaluation
Hemolytic screen
FBC, blood smear, LDH, haptoglobin, bilirubin, DAT, reticulocyte count with or without urine for hemosiderin or urine dipstick for microscopy
Detection of underlying disorders (investigation of AIHA)
Serum Igs and electrophoresis with immunofixation*
HIV, HBV, HCV
Anti-dsDNA, ANA
CT chest, abdomen, and pelvis
Additional investigation in selected patients with AIHA
Bone marrow examination	CAD, age ≥ 60 years, features in history, examination, FBC or smear suggesting possible marrow infiltration
U&E, LFT, clotting, BP, urine dipstick	If pregnant or thrombocytopenic, to exclude DIC or pregnancy-associated TMA
Infection screening	Dependent on symptoms, travel history, and age
Peripheral T-cell subsets, creatinine, LFT, clotting	All children and if suspected Evans syndrome
Parvovirus, hematinics	If reticulocytopenia
Additional serological investigation in selected patients with AIHA
DAggT	If DAT positive for C3d ± IgG
Cold antibody titer	If DAggT positive
Monospecific DAT for IgM, G, A, C3d	If DAT-negative AIHA suspected
Red cell eluate	If (monospecific) DAT-negative AIHA suspected
Donath Landsteiner	If DAT is positive for C3d ± IgG and
	i) DAggT-negative or insignificant CAs and
	ii) Age < 18 y or hemoglobinuria or cold-associated symptoms or atypical serology
Thermal range of cold antibody	If clinical significance of cold autoagglutinin unclear

ANA, antinuclear antibody; BP, blood pressure; CAD, cold agglutinin disease; CAs, cold agglutinins; CT, computerized tomography; DAggT, direct agglutination test; DIC, disseminated intravascular coagulation; dsDNA, double-stranded DNA; FBC, full blood count; HBV, hepatitis B virus; HCV, hepatitis C virus; LFT, liver function tests; TMA, thrombotic microangiopathy; U&E, urea and electrolytes.

^*If a cold autoantibody suspected, keep sample at 37°C until serum has been separated.

Modified from Hill et al, with permission.¹²