Objective: In quantitative analysis of serum proteins turbidimetric and nephelometric methods are the
most common. Aim of this study was to compare the nephelometric method with the turbidimetric
method for serum and urine samples in our clinical laboratory and to analyse the performance of the
turbidimetric method.
Material and Methods: 24 hours collected urine albumin ( n=146), spot urine albumin (n=78), serum
ASO (n=30), serum RF (n=48), serum IgA (n=24), IgM (n=24), IgG (n=24) and IgE (n=74) were
analyzed with Behring BN II (Siemens, Germany) and Architect C 16000 (Abbott, USA). The relationship
between the turbidimetric and nephelometric methods was demonstrated by applying the non –
parametric method of Passing&Bablok. Each parameter's regression coeffiency and regression equation
with intercept and slope value, Standart error, Standart error of mean (Syx) were checked. Correlation
coefficients of serum plasma proteins and microalbumin levels were determined by linear regression
analysis.
Results: There wasn't any significant difference between nephelometric and turbidimetric methods
(correlation coefficiency: 0.996, 0.999, 0.991, 0.967, 0.930, 0.847, for 24 hour and spot microalbumin,
Ig A, M, G and E respectively). % 95 CI was (0.995-0.997) for 24 hour microalbumin and for (0.999-1)
for spot microalbumin results. For Ig A, M, G and IgE test results % 95 CI lower and upper limits were
(0.976-0.996), (0.913-0.987), (0.828-0.972) and (0.757-0.904), respectively. Intercept and slope values
were (-1.58, 1.07), (0.40, 0.92), (-1.63, 1.2),(-0.95, 1.22),(112.83, 1.06) and (-12.24, 1.19), respectively.
Conclusion: Our results indicated that the turbidimetric and nephelometric methods were compatible.