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Home / Equine Research Bank / Acta Vet Scand / Evaluation of an in-clinic Serum Amyloid A (SAA) assay and a...
Acta veterinaria Scandinavica2010; 52(1); 8; doi: 10.1186/1751-0147-52-8

Evaluation of an in-clinic Serum Amyloid A (SAA) assay and assessment of the effects of storage on SAA samples.

Abstract: An in-clinic assay for equine serum amyloid A (SAA) analysis, Equinostic EVA1, was evaluated for use in a clinical setting. Stability of SAA in serum samples was determined. Methods: Intra- and inter- assay variation of the in-clinic method was determined. The in-clinic method (EVA1) results were compared to a reference method (Eiken LZ SAA) with 62 patient samples. For samples with SAA concentrations within the assay range of EVA1 (10-270 mg/L), differences between the methods were evaluated in a difference plot. Linearity under dilution was evaluated in two samples. Stability of SAA in three serum pools stored at 4 degrees C and approximately 22 degrees C was evaluated with the reference method day 0, 1, 2, 4, 7, 17 and analysed with a two-way ANOVA. Results: The imprecision (coefficient of variation, CV) for the in-clinic method was acceptable at higher SAA concentrations with CV values of 7,3-12%, but poor at low SAA concentrations with CV values of 27% and 37% for intra- and inter-assay variation respectively. Recovery after dilution was 50-138%. The in-clinic assay and the reference method identified equally well horses with low (<10 mg/L) and high (>270 mg/L) SAA concentrations. Within the assay range of the in-clinic method, 10-270 mg/L, the difference between the two methods was slightly higher than could be explained by the inherent imprecision of the assays. There were no significant changes of serum SAA concentrations during storage. Conclusions: The in-clinic assay identified horses with SAA concentrations of <10 mg/L and >270 mg/L in a similar way as the reference method, and provided an estimate of the SAA concentration in the range of 10-270 mg/L. The imprecision of the in-clinic method was acceptable at high SAA concentrations but not at low concentrations. Dilution of samples gave inconsistent results. SAA was stable both at room temperature and refrigerated, and thus samples may be stored before analysis with the reference method.
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Publication Date: 2010-02-02 PubMed ID: 20122257PubMed Central: PMC2831015DOI: 10.1186/1751-0147-52-8Google Scholar: Lookup
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  • Evaluation Study
  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The study investigates the reliability and applicability of an in-clinic equine serum amyloid A (SAA) test, Equinostic EVA1, compared to a reference method. It also looks into the stability of serum SAA samples under various storage conditions.

Study Objectives and Methods

  • The researchers aimed to evaluate an in-clinic EVA1 test’s accuracy and reliability when measuring equine serum amyloid concentrations.
  • A variance study was conducted to determine the consistency of results from the in-clinic method.
  • Differences between in-clinic and referenced method results were examined on 62 patient samples. For those within the EVA1 test range, the findings were represented on a difference plot.
  • Dilution linearity was tested on two samples to assess the assay’s performance under different concentrations.
  • Focusing on the stability of SAA in serum samples, they stored the samples at two different temperatures (4 degrees C and approximately 22 degrees C) and measured the concentrations over a period of 17 days using a two-way ANOVA analysis.

Findings

  • Results showed that imprecision in the EVA1 method became less accurate at lower SAA concentrations. At higher SAA concentrations, the in-clinic method offered acceptable coefficient variation (CV) values between 7.3% and 12%, but proved to be less reliable at lower concentrations with CV values at 27% and 37% intra- and inter-assay variation, respectively.
  • The SAA recovery rate after dilution ranged from 50% to 138%, indicating inconsistent results post-dilution.
  • The in-clinic method and reference method equally identified horses with low and high SAA concentrations. However, for samples within the EVA1 test range (10-270 mg/L), the difference in results from the two methods was significantly larger than the expected normal variance.
  • No significant changes in serum SAA concentrations were observed during storage, indicating that SAA remains stable at both room temperature and refrigeration levels.

Implications and Conclusions

  • The results suggest that the in-clinic EVA1 method has limitations when testing lower SAA concentrations. The method’s precision is acceptable for high SAA concentrations, but reliability is compromised at lower levels.
  • Diluting samples for the assay does not always lead to consistent findings, which may affect the assay’s overall reliability.
  • The EVA1 in-clinic method and the reference approach accurately identify horses with low and high SAA concentrations, however, they differentiate slightly for samples within the assay range of 10-270 mg/L.
  • Given the observed stability of SAA during storage, results suggest refrigeration is not necessary and samples can be stored at room temperature before analysis with a reference method.

Cite This Article

APA
Hillström A, Tvedten H, Lilliehöök I. (2010). Evaluation of an in-clinic Serum Amyloid A (SAA) assay and assessment of the effects of storage on SAA samples. Acta Vet Scand, 52(1), 8. https://doi.org/10.1186/1751-0147-52-8

Publication

Acta veterinaria Scandinavica
ISSN: 1751-0147
NlmUniqueID: 0370400
Country: England
Language: English
Volume: 52
Issue: 1
Pages: 8

Researcher Affiliations

Hillström, Anna
  • University Veterinary Hospital, Swedish University of Agricultural Sciences, 750 07 Uppsala, Sweden. anna.hillstrom@uds.slu.se
Tvedten, Harold
    Lilliehöök, Inger

      MeSH Terms

      • Animals
      • Diagnostic Tests, Routine / methods
      • Diagnostic Tests, Routine / veterinary
      • Horse Diseases / diagnosis
      • Horses
      • Inflammation / diagnosis
      • Inflammation / veterinary
      • Reproducibility of Results
      • Sensitivity and Specificity
      • Serum Amyloid A Protein / analysis
      • Temperature
      • Time Factors

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