Serum Protein Assays Validated for Autoanalyzer

The autoanalyzer is designed to perform potentiometric and photometric assays in serum, plasma, urine, and cerebrospinal fluid, as well as various supernatant sample types.

The assays were developed by scientists at the Foundation for Blood Research, (Scarborough, ME, USA), using de-identified, surplus serum samples stored at -20 °C for less than two months. Samples were selected to encompass a broad range of analyte concentrations and were used for the method comparison studies. The 14 human serum proteins assayed were 1-antitrypsin, 2-macroglobulin, albumin, apolipoproteins AI and B, complement components 3 and 4, haptoglobin, immunoglobulins A, G, and M, orosomucoid, transferrin, and transthyretin. The autoanalyzer used was the versatile Roche cobas c 501, (Roche Diagnostics; Indianapolis, IN, USA), which is from their 6000 series.

Immunoturbidimetric assays for 12 of the 14 proteins were developed using monospecific goat antihuman serum from Midland BioProducts Corporation (Boone, IA, USA). For assaying α-1-antitrypsin and α-2-macroglobulin, goat antihuman serum was obtained from International Immunology Corporation (Murrieta, CA, USA) and DiaSorin (Stillwater, MN, USA), respectively.

The scientists obtained excellent precision at low, normal, and high physiologic concentrations of each protein. Linearity for each method was within 5% of the expected value throughout the calibration range, and method comparison studies to commercial assays were in good agreement. No significant interference was observed from bilirubin, up to 414 mg/L, hemoglobin up to 8.9 g/L, triglyceride, up to 28 g/L, or rheumatoid factor, up to 3,930 IU/mL. Calibration was stable for at least 14 days. The instrument's small reaction cell allowed conservation of nearly 60% of the specimen and reagent volume compared with another system.

The scientists concluded that these newly developed assays provide precise and accurate results with high throughput, but without the associated cost of a dedicated instrument. The study was published on January 19, 2011, in the Journal of Clinical Laboratory Analysis.

Related Links:
Foundation for Blood Research
Roche Diagnostics
Midland BioProducts Corporation
International Immunology Corporation
DiaSorin