Immunoturbidimetry methods have become the main technique for performing protein tests. The transition from nephelometry has been cautious but is increasing as laboratories enjoy the comparability and flexibility of immunoturbidimetry.

Immunoturbidimetry and nephelometry both measure the turbidity of a sample to determine the level of an analyte. Upon addition of the assay reagent, antibodies and antigen cluster to form an immune complex that precipitates, increasing the turbidity of the sample. When light is passed through the reaction solution, some light is scattered by the sample, some light is absorbed by the sample and the rest passes through the sample.

Immunoturbidimetry measures the absorbance of the light by the sample, nephelometry measures the light scattered at a fixed angle. The level of analyte is determined by comparison with a calibrator of known concentration.

Immunoturbidimetry is ideal for the detection of proteins, where the analyte concentration is inversely proportional to the transmitted light signal. Historically nephelometry has been more sensitive than conventional immunoturbidimetry. In latex-enhanced immunoturbidimetry, inert microscopic particles enlarge the immune complexes, amplifying the reaction and significantly increasing the sensitivity of the reaction.

Nephelometers are dedicated analysers only capable of performing this type of assay. In addition, they are:

• slow
• have high consumable costs
• require highly trained personnel

Immunoturbidimetric tests are carried out on routine biochemistry analysers that are:

• versatile
• fast
• cost-effective
• offer longer reagent stability
• sensitive

The main advantage of nephelometry was its sensitivity; however latex-enhanced immunoturbidimetry has closed this gap.   Immunoturbidimetric tests are an increasingly accepted alternative to nephelometry for specific protein assays, and studies have shown a close correlation between Randox immunoturbidimetric tests and nephelometry.

If you are interested in running your protein assays on a routine biochemistry analyser, Randox offers a large range of high quality routine and niche protein assays that can be run on most automated analysers, including:  Alpha-I acid glycoprotein; alpha-I antitrypsin; anti-streptolysin O; apolipoprotein A-I; apolipoprotein A-II; apolipoprotein B; apolipoprotein C-II; apolipoprotein C-III; apolipoprotein E; ceruloplasmin; complement C3; complement C4; CRP; cystatin C; ferritin; haptoglobin; HbA1c; IgA; IgE; IgG; IgM; lipoprotein (a); microalbumin; myoglobin; rheumatoid factor; transferrin and transthyretin (prealbumin).  For more information, download our Reagents Brochure or email: reagents@randox.com.