Turbidimetric Equine SAA Assay System
The benefits of testing for Serum Amyloid A (SAA) in Equines as both an indicator of potential performance and of the health status of the horse are well documented and have been discussed in other areas on the website.
SAA is becoming an increasingly important parameter in horses, and this has resulted in increasing demand for sample analysis and in the number of tests being performed, resulting in the need for fast turnaround of high volumes of assays.
Tridelta has responded to requests from customers for a specific equine turbidimetric assay which will meet these needs with the same levels of performance and accuracy as our well-known and established Multispecies SAA ELISA Assay. (Cat. Number: TP-802)
Tridelta Turbidimetric Equine SAA Assay system is now available.
The Assay system utilises a specific and proprietary anti-Equine SAA antibody, developed by Tridelta and is in modular format consisting of three separate components for maximum efficiency and economy:
Turbidimetric Equine SAA Reagent (Cat. # TE-501-RGT)
Turbidimetric Equine SAA Calibrator (Cat. # TE-501-CAL)
Turbidimetric Equine SAA Control (Cat. # TE-501-CON)
- all available individually to suit the needs of each laboratory and it’s workload. The reagent kit is optimised to perform 200 tests, dependent on the instrument used.
Technical details and individual data sheets and methodologies for each component are available for download by clicking on the relevant title in the side bar on the right-hand side of this page.
The assay system can be adapted to any autoanalyzer which meets the requirements stated, providing a rapid, high throughput assay for fast and economic turnaround of SAA tests.
A prime requirement of the turbidimetric assay is that it correlates with the SAA ELISA assay which has been an effective “gold standard” in this field for many years.
The following graph is the result of testing a large number of equine serum samples (n = 108) covering a very broad range of SAA concentrations (from zero to 12.2mg/ml) in both the new Tridelta Turbidimetric Equine SAA assay and the Tridelta MultispeciesSAA ELISA Assay (TP-802).
The regression equation (using an intercept of zero) and r2 values were calculated to be y=0.991x and 0.9318 respectively, showing that this method can be used reliably to calculate SAA concentrations in equine serum.
Accuracy and reliability are key parameters in using any assay and it is of particular importance that factors such as the “hook effect” are not an issue affecting assay performance and resulting in erroneous results being produced with potentially serious consequences.
The assay was rigorously tested in this respect and no hook effect was observed when a sample pre dilution of 1:5 was carried out, flowed by a reflex dilution of 1:10, up to and including extreme SAA concentrations of 12.2 mg/ml (DOF p45)
Stability
The calibration curve, when established on the instrument, is stable for a period of at least 3 weeks. Daily controls should be run and if the controls return within the expected range there is no need to re-calibrate – however, if controls are out of range, it is recommended that the calibration curve be re-run.
Analytical Sensitivity
The sensitivity of the assay, when used on the Cobas Mira Plus is determined as 4.68ug/ml
Measuring Range
The upper limit of the assay is dependent on the highest calibration point value of the calibration curve: 400ug/ml. When a sample pre-dilution of 1:5 is used this nis extended to 2000ug/ml. For the extremes of measuring, a further reflex dilution of 1:10 can be used which extends the measuring range to20mg/ml.
Precision
Inter and Intra Assay Precision were measured with the following results:
Temperature: In Use and Storage
The different components of the assay: Reagents, Control and Calibrators, should be used and stored at the stated operating temperatures.
It should be particularly noted that the Reagent Pack (as distinct from the Control and Calibration packs) should not be refrigerated but should be maintained at Room Temperature.
In the case of an analyser where the regent block is refrigerated, this should be switched off: if the refrigeration cannot be switched off, then the reagents have been shown to be stable for use under these conditions up to a maximum period of 90 minutes at a time before being restored to Room Temperature. This process may be repeated as long as the maximum period is not exceeded in any given session and the reagents are returned to and stored at, room Temperature.
Control and calibration packs should be used and stored as per the instruction provided. Control may be used and returned to the fridge for storage and continuing use.
The New Equine Turbidimetric SAA Assay is now available to order directly from Tridelta or via your local Tridelta Distributor.
