Dear Drs. Hinchcliff and DiBartola,
We read with great interest the recent article DOI:http://doi.org/10.1111/jvim.15039, entitled “Evaluation of SNAP cPL, Spec cPL, VetScan cPL Rapid Test, and Precision PSL Assays for the Diagnosis of Clinical Pancreatitis in Dogs” by Cridge et al. and we applaud the authors for their efforts in comparing various diagnostic tests currently available for the diagnosis of canine pancreatitis. However, we would like to highlight some important limitations that should be taken into consideration when reading this manuscript. All of the diagnostic tests utilized in this study were performed under field conditions, except the VetSan cPL Rapid Test, which was not performed patient‐side as intended, but was performed at Abaxis Laboratories in Union City, CA, which, to our knowledge, is a research facility rather than a service laboratory. One may consider this to be just a minor matter being that the equipment and the assay kits utilized should be the same as those utilized under field conditions. However, this is not the case, because shipping the kits to veterinary clinics and storage at veterinary facilities under uncontrolled conditions, as specified by the manufacturer of this kit, may have an important impact on assay performance. It should also be noted that no analytical validation data for the VetScan cPL Rapid Test are publically available. Because of this, our laboratory performed an analytical validation study under field conditions. The assay was found to show poor linearity. More importantly, the assay was not precise and had unacceptable reproducibility with a mean inter‐assay coefficient of variability of 31.8%. Most samples retested multiple times gave results in two or even three different diagnostic bins (i.e., normal, questionable, or suggestive of pancreatitis). Almost none of the samples had results within ±65 µg/L of Spec cPL results as suggested by the manufacturer. Unfortunately, we cannot report more‐detailed results of our analytical validation study in this letter as these data are currently under review. However, clearly, determining agreement of an assay with other diagnostic assays when under field conditions the assay fails to agree with itself is concerning. We would therefore like to caution readers that the conditions used for assessing the VetScan cPL Rapid Test described in this manuscript may have led to results that cannot be replicated under field conditions.
Sincerely,
Joerg Steiner, DMV, PhD, DACVIM (SAIM), DECVIM‐CA;
Jonathan Lidbury, BVMS, MRCVS, PhD, DACVIM (SAIM), DECVIM‐CA; Texas A&M University, College Station, TX.
CONFLICT OF INTEREST DECLARATION
Drs. Lidbury and Steiner are affiliated with the Gastrointestinal Laboratory Texas A&M University, which offers measurement of Spec cPL concentrations on a fee‐for‐service basis. Dr. Steiner is also a consultant for IDEXX Laboratories, the manufacturer of the Spec cPL and SNAP cPL assays. Both Drs. Steiner and Lidbury have acted as paid speakers for IDEXX Laboratories.
Correspondence
Journal of Veterinary Internal Medicine, Greenwood Village, Colorado.
Email: JVIM@ACVIM.org