Akademik Veri Yönetim Sistemi
XXXIII. WASPaLM World Congress & XXIV. National Clinicial Biochemistry Congress, Antalya, Türkiye, 16 - 20 Ekim 2024, ss.47
Aim: Serum protein electrophoresis is frequently used for the detection of monoclonal gammopathies.
In serum protein electrophoresis, the concentrations of albumin and other bands can be determined
using total protein results. Serum albumin measurement can be used for many purposes such as
assessment of nutritional status, liver and kidney function, and prediction of corrected calcium results.
Additionally, low albumin levels are associated with high mortality, and appropriate therapeutic use
has been shown to improve prognosis. In this study, we aimed to investigate whether albumin
concentrations obtained in different serum protein electrophoresis patterns can be used instead of
albumin concentrations determined by direct measurement.
Method: The data used were obtained from 373 patients aged 18-90 years with serum protein
electrophoresis, total protein, albumin and immunoglobulin results with the same barcode number
analyzed between 01.09.2023 and 01.09.2024 in the Medical Biochemistry Laboratory of Eskişehir
Osmangazi University Hospital. Patients with hemolysis index>500, icteria index>20, lipemia
index>550, CRP>5 mg/L and patients with biclonal gammopathy were excluded. Serum protein
electrophoresis was performed with Helena V8 Nexus (Helena Biosciences, Gateshead, UK) capillary
electrophoresis. Total protein, albumin and immunoglobulin levels were analyzed on a Cobas c702
(Roche Diagnostics, Mannheim, Germany) autoanalyzer using the biuret method, bromcresol green and
immunoturbudimetric method, respectively. The relationship between serum protein electrophoresis and
direct albumin measurements was evaluated by Method comparison & evaluation Bland-Altman plot
analysis and Passing-Bablok regression analysis using MedCalc V22.023. In addition, the analysis was
done in the subgroups that were created according to concentrations of total protein, Ig G and gamma
band and presence/absence of monoclonal gammopathy. To assess clinical significance, the total
acceptable error that calculated with intra-individual and inter-individual variations was obtained by
median of direct albumin concentrations. The mean biases compared with the total acceptable error.
Results: When all patients were evaluated, although showed no significant deviation from linearity
between serum protein electrophoresis and direct albumin measurements in Passing-Bablok regression
analysis [P=0.49, y = -0.61 + 1.08 x , (slope: 1.04 to 1.12, 95% Cl), (intercept: -0.76 to -0.46, 95%
Cl)], mean bias 0.28 g/dL and the difference between the two methods was highly significant in Bland-
Altman plot analysis (P<0.0001). Since the mean bias was above the total acceptable error, it was
considered clinically significant. Although Passing-Bablok regression analysis was linear in all other
subgroups (P>0.05) and intercept confidence interval included 0 and slope confidence interval
included 1 in some groups, the mean bias in Bland-Altman plot analyses was found to be above the
clinical significance level.
Conclusion: Regardless of total protein, Ig G, M-spike and gamma band levels, albumin concentrations
calculated by serum protein electrophoresis were lower than those measured by bromcresol green in
all groups and were considered clinically significant. Therefore, albumin levels calculated by serum
protein electrophoresis cannot be used as a substitute for direct albumin measurement using
bromcresol green method.
Keywords: Blood protein electrophoresis, serum albumin, bromcresol green