Validation of Calculated Globulin (CG) as a Screening Test for Antibody Deficiency in an Italian University Hospital

Author(s): Antonio Pecoraro, Stephen Jolles, Ludovica Crescenzi, Gilda Varricchi, Giancarlo Marone, Marcella Savoia, Arturo Genovese, Giuseppe Spadaro*.

Journal Name: Current Pharmaceutical Biotechnology

Volume 19 , Issue 9 , 2018

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Graphical Abstract:


Background: Morbidity and mortality of primary and secondary antibody deficiencies (AD) are frequently associated with diagnostic delays. These could be avoided by a combination of factors including a widespread and effective development in screening tests.

Methods: Calculated globulin (CG), derived from the difference between serum total protein and albumin levels, reflects immunoglobulin serum levels and has shown to have a predictive value in the early diagnosis of antibody deficiencies. This study investigated the possibility to use low levels of CG to detect antibody deficiency in an Italian University Hospital.

Results: First, we conducted an analysis of anonymized adult samples collected at our biochemistry laboratory with a range of calculated globulin levels from 15 to 22 g/l. A CG cut-off of 19 g/l detected subjects with IgG lower than 600 mg/dl with a sensitivity of 70% and a specificity of 75%. To further verify the clinical usefulness of CG, we retrospectively evaluated the relationship between CG values and serum IgG levels in 38 patients diagnosed with CVID at our Institution. Using a CG cut-off of 19 g/l, we detected antibody deficiency in 97.3% (37/38) of the subjects present in our cohort.

Conclusion: Finally, we chose a CG value of 19 g/l as the cut-off for a prospective AD screening program. The results of this study show that a screening CG test can be used as a tool to reduce diagnostic delays, improve long-term prognosis and reduce the healthcare costs of antibody deficiency.

Keywords: common variable immunodeficiency (CVID), primary antibody deficiency (PAD), secondary antibody deficiency (SAD), calculated globulin (CG), AD screening.

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Article Details

Year: 2018
Page: [728 - 733]
Pages: 6
DOI: 10.2174/1389201019666180808163311
Price: $58

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