Analytical validation of commercially available methods for acute phase proteins quantification in pigs

Area of Science:

• Veterinary diagnostics
• Biochemical analysis
• Animal health monitoring

Background:

• Accurate quantification of acute phase proteins (APPs) is crucial for diagnosing inflammation and disease in pigs.
• Commercially available assays offer convenience but require validation for specific species and applications.

Purpose of the Study:

• To validate the performance of commercial assays for porcine haptoglobin (Hp), C-reactive protein (CRP), serum amyloid A (SAA), and Pig Major Acute Phase Protein (Pig-MAP).
• To assess the reliability and limitations of these assays under various conditions, including interfering substances and induced inflammation.

Main Methods:

• Validation of four commercial APP assays (Hp, CRP, SAA, Pig-MAP) using standard laboratory procedures.
• Assessment of intra- and inter-assay coefficients of variation (CVs), linearity, and detection limits.
• Evaluation of the impact of haemolysis and lipaemia on assay results.
• Induction of inflammation in pigs using turpentine to evaluate assay responsiveness.

Main Results:

• Most assays demonstrated CVs below 20%, with exceptions for CRP and Pig-MAP at low concentrations and SAA at all concentrations.
• All methods exhibited good linearity and sufficiently low detection limits for healthy animals.
• Haemolysis significantly affected Hp and SAA, while lipaemia primarily impacted SAA.
• Induced inflammation led to >15-fold increases in CRP and SAA, and <5-fold increases in Hp and Pig-MAP.

Conclusions:

• Commercial assays for porcine Hp, CRP, SAA, and Pig-MAP are largely suitable for detecting APPs in healthy and inflamed animals.
• Assay performance can be affected by haemolysis, lipaemia, and low analyte concentrations, necessitating careful sample handling and interpretation.
• CRP and SAA show greater sensitivity to induced inflammation compared to Hp and Pig-MAP.