Diagnostic lag is a significant issue for uncommon illnesses such as primary antibody deficiency (PAD). The goal of this review is to explore the potential and difficulties of existing and future antibody deficiency screening techniques in order to decrease the delay and its impact on patients. Delays in diagnosing PAD are known to increase morbidity, death, and irreversible functional disability. Approaches to prevention have only been somewhat successful, and the delay may still be several years because the clinical presentation of PAD is very varied and can occur at any age, making screening challenging. Before a diagnosis is determined, patients may have many healthcare contacts, resulting in multiple cycles of laboratory and clinical data. Low immunoglobulin levels affect laboratory tests that are not specifically designed to measure immunoglobulins. We explain these and highlight the rising data supporting the use of computed globulin, which is part of the liver function test profile, as a screening tool for antibody deficiency. Other techniques involve utilizing embedded algorithms to analyze data collected by repeated clinical encounters, perhaps in conjunction with test results like calculated globulin, to aid in the diagnosis of PAD in patients who have not yet been evaluated.
Calculated globulin has a good case for use in screening for antibody deficiency. More research is needed to combine laboratory results with clinical data in order to decrease diagnosis delays in individuals with previously undetected antibody deficiency.