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Clinical Pathology  

Clinical Pathology

Instrument Change for Chemistry Analyzer

On Tuesday November 21, 2017, our old chemistry analyzer is being replaced. This means that on Monday November 20th, chemistry results will be provided from our old analyzer (ModP) whereas on Tuesday November 21st, results will be provided from our new analyzer (Cobas).

To determine whether changes in test results with sequential testing of patients are due to the patient (e.g. disease) or change in the machine, a summary of the correlations we have done for the species we routinely test or have reference intervals for is available on our Chemistry Reference Intervals page. This chart has the following data: Number of samples, correlation coefficient, minimum and maximum of tested values, mean bias in absolute units, mean bias as a percentage of old analyzer results, and slope and intercept for a Deming regression equation along with notes of observations made regarding the correlation. The raw data (graphs etc) are available on request. Note that a negative bias means the new machine reads lower than the old and vice versa for a positive bias.

You will also note that there is a change of reagent for creatine kinase (CK). The new machine will have the new reagent for CK.

Other notable changes:

  • We have changed our bile acid reagent which is based on the same reactions but is a 5th versus 3rd generation reagent. The major change is that the cycling of the reaction is now monitored. We have noted that the new reagent is far less impacted by hemolysis and lipemia versus the older one, which is a good thing. We have established new fasting/random reference intervals for all species and will be providing new reference intervals for bile acids (random) for large animals. For small animals, we will not provide intervals, but rather a standard comment based on guidelines used at Cornell.
  • The fructosamine reagent provides higher results than that obtained previously due to changes in reagent concentration and pH of the reaction. Our new intervals do reflect these increases.

We have also established new reference intervals for our biochemical test results from our new analyzer, including the new CK and bile acid reagents. These reference intervals are also available on our Chemistry Reference Intervals page. Please note, that we established new intervals for goats and llamas by using Deming regression equations on correlations as we did not collect new samples from these species for reference interval determination.

We would like to take the opportunity to thank all of those who assisted with these studies, by either providing samples or their pets for deriving new intervals and performing the correlations. We would also like to thank the clinical pathology staff for their tremendous efforts as these studies were done on top of our heavy daily workload.

In the next few months, we will be validating our current hematology intervals (we have a new analyzer there too) and more information will be forthcoming on correlations and interval changes for hematology.

If you have any questions, please contact Tracy Stokol, laboratory director or Gail Babcock, our laboratory manager.