Background and Aims

Background: Serum electrophoresis, total protein, and albumin determinations have a variety of applications in clinical practice, but their full potential is yet to explored. The evaluation of calculated globulin (CG) (total protein – albumin) and gamma fraction (GF) (from protein electrophoresis) values can provide relevant data on humoral immunity. The aim of this study was to investigate the correlation between CG and IgG, and GF and IgG levels, by age range.

Methods

Methods: A multicenter prospective, 2-year study was initiated testing for CG, protein electrophoresis, and IgG levels in pediatric and adult patients.

Results

To date 1079 patients have been evaluated (Table 1). A linear relationship between CG and IgG, GF, and IgG levels was found across eight pediatric age ranges, adults, and the pooled analyzed data (Figures 1A-J, 2A-J). Calculated globulin and GF cut-off values were established to detect IgG levels below the 3^rd percentile of normal ranges for each age group and presented acceptable accuracy for most age groups. (Table 2).

The mean difference between IgG and GF values was significantly different from zero only in the ages ranges 1-2 and > 18 years (Figure 3).

Conclusions

CG and IgG values, and GF and IgG correlate in a linear manner. CG and GF are promising screening tests to detect antibody deficiencies. The collection of additional samples will power this study in determining the cut-off values for both pediatric and adult age ranges.

Acknowledgments: The authors would like to acknowledge CSL Behring, Shire, and Jeffrey Modell Foundation for support.