What are the key laboratory tests to consider when evaluating a patient with suspected autoimmune disease?

When evaluating a patient with suspected autoimmune disease, the key laboratory tests to consider are highly dependent on the specific condition suspected ¹,²,⁶. For instance, in cases where Systemic Lupus Erythematosus (SLE) is suspected, the evaluation of anti-dsDNA antibodies is a key consideration (Cockx et al., 2022). However, it is important to note that some autoimmune diseases can be seronegative, meaning typical autoantibodies may not be present, posing a diagnostic challenge (Lenti et al., 2022).

For suspected coeliac disease, initial tests typically include tissue transglutaminase (tTG) antibodies, and if these are positive, endomysial antibodies (EMA) may also be considered ¹,⁶. In the context of suspected type 1 diabetes, relevant autoantibodies include islet cell antibodies (ICA), glutamic acid decarboxylase (GAD) antibodies, insulin autoantibodies (IAA), and tyrosine phosphatase-like antigen (IA-2) antibodies ²,³. The absence of typical serological markers does not always rule out an autoimmune condition, especially in the case of seronegative autoimmune diseases (Lenti et al., 2022).