Introduction
Acute abdomen syndrome is a common term applied to sudden nonspecific gastrointestinal signs in dogs, including vomiting, lethargy, weakness, abdominal pain, hyporexia, anorexia, or diarrhea.1,2 Common differential diagnoses for acute abdomen syndrome include gastroenteritis, acute pancreatitis, hepatobiliary disease, urinary obstruction, and gastrointestinal foreign body obstruction (GIFBO). Thorough patient evaluation with a combination of general blood work (eg, CBC and biochemical profile), urinalysis, various disease-specific tests (eg, parvovirus test), and abdominal imaging is often required to ensure proper diagnosis and to initiate appropriate treatment. Early differentiation between medical and surgical causes is critical because delayed diagnosis in patients with GIFBO can increase patient risk for morbidity and death.3,4 Differentiation can be challenging when practices have limited abdominal imaging availability.
The diagnosis of acute pancreatitis in dogs is aided by a point-of-care semiquantitative test that measures serum concentration of pancreas-specific lipase (SNAP cPL test kit; Idexx Laboratories Inc) and was developed to screen patients at the time of initial presentation. Results of the SNAP canine pancreatic lipase (cPL) test have been shown to have good correlation with the quantitative specific cPL (Spec cPL) concentration measurements.1 A normal SNAP cPL test result corresponds to a Spec cPL < 200 µg/L (consistent with absence of pancreatic inflammation), whereas an abnormal SNAP cPL test result corresponds to a Spec cPL ≥ 200 µg/L. Reported sensitivity and specificity of the SNAP cPL test for diagnosing acute pancreatitis range between 73.9% to 100% and 59% to 77.8%, respectively.1,5,6 A normal SNAP cPL test result makes acute pancreatitis a less likely etiology for the acute abdominal signs. Manufacturer recommendation for when an abnormal SNAP cPL test result is obtained is to confirm the result with a quantitative Spec cPL test, abdominal ultrasonography, or both, although this may not always occur in clinical practice, as an abnormal result may bias clinicians and delay the urgency of confirmation.7 A false-positive diagnosis of acute pancreatitis by use of the SNAP cPL test has been previously reported in up to 40% (11/27) of dogs with acute abdomen syndrome.1
In previous studies, a limited number of GIFBO cases have been included in the evaluation of SNAP cPL test results. One study1 included a total of 7 GIFBO dogs lacking evidence for concurrent acute pancreatitis and found that 42.9% (3/7 dogs) had abnormal SNAP cPL test results, which could lead to an inaccurate diagnosis of acute pancreatitis based on those results alone. It is unknown whether dogs with GIFBOs may be more likely to produce an abnormal SNAP cPL test result. Investigation is required to guide veterinarians in their diagnostic evaluation when presented with patients exhibiting acute abdominal syndrome of which both GIFBO and acute pancreatitis are differential diagnoses of concern.
The primary objective of the study reported here was to prospectively determine the proportion of abnormal SNAP cPL test results in a larger canine population confirmed to have GIFBO without clinical evidence of acute pancreatitis. These results were compared to a control population of dogs with medical causes of acute abdomen syndrome (excluding acute pancreatitis) to evaluate whether dogs with GIFBO are more likely to have abnormal SNAP cPL test results. A secondary objective was to evaluate for clinical associations with abnormal SNAP cPL test results in dogs without acute pancreatitis. Our hypothesis was that dogs with GIFBO would have a significantly higher proportion of abnormal SNAP cPL test results than would dogs without GIFBO.
Materials and Methods
This study was reviewed and approved by the BluePearl Veterinary Partners Institutional Review Board. Client-owned dogs presented to the BluePearl Southfield emergency service between April 2019 and January 2021 were eligible for enrollment. Inclusion criteria consisted of the following: (1) dogs had to have had clinical signs supportive of acute abdomen syndrome (ie, vomiting, diarrhea, hyporexia or anorexia, or abdominal pain), (2) owners had to have consented to blood work and abdominal ultrasonography at the time of initial presentation, and (3) abdominal ultrasonography had to have found no evidence to suggest the diagnosis of acute pancreatitis. Dogs with acute abdomen syndrome were excluded if they had blood work findings that may have suggested the diagnosis of acute pancreatitis (ie, high activities of amylase or lipase) or had ultrasonographic findings consistent with acute pancreatitis (ie, pancreatic enlargement, pancreatic irregularity, changes in pancreatic echogenicity and echotexture, changes in echogenicity of the surrounding mesentery, or evidence of peripancreatic free fluid).8 All abdominal ultrasounds were performed by a single board-certified veterinary radiologist. Dogs were classified into either the GIFBO group or non-GIFBO control group on the basis of ultrasonographic findings.
Owner consent was acquired in all patients before SNAP cPL tests were performed. All blood work and SNAP cPL tests were completed within 24 hours of initial presentation and prior to surgical intervention. SNAP cPL tests were performed by use of serum, and manufacturer instructions were followed regarding the storage of SNAP cPL kits, sample processing, temperature equilibration, and testing. All SNAP cPL tests were performed and interpreted by the primary author (BDL), with results recorded as visually normal or abnormal. Tests were repeated in instances of equivocal results due to indistinguishable control and test spot intensities, and consecutive similar intensities were classified as an abnormal result.
Information collected from each animal included presenting clinical signs, physical examination findings, body weight, all hematologic test results, ultrasonographic findings, SNAP cPL test result, and, for those dogs in the GIFBO group, the intraoperative location of obstruction, gross evaluation of the pancreas, and surgical procedure(s) performed. In the non-GIFBO control group, a final diagnosis for the underlying etiology of acute abdomen syndrome was recorded when available.
Statistical analysis
A total of 25 dogs were initially enrolled into each group. This sample size was set to establish an estimation of a proportion of abnormal SNAP cPL results for each group. After the first 25 dogs were enrolled in each group, data were preliminarily analyzed, and a post hoc power analysis was performed. On the basis of statistical findings, it was elected to stop enrollment and complete the study with 25 dogs/group. Normality was determined for continuous data by use of the D’Agostino-Pearson method and visual examination of Q-Q plots. Normally distributed data were presented as mean (± SD), and nonnormally distributed data were presented as median (range). Categorical data between and within the GIFBO and non-GIFBO groups were compared by use of the Fisher exact test (any count < 5) or χ2 test. Continuous data were compared by use of either an unpaired t test or Mann-Whitney U test on the basis of normality results. Analysis was performed with standard software (Prism version 9.0.1; GraphPad Software LLC). Significance was set at P < 0.05 for all tests.
Results
Non-GIFBO control group
Twenty-five dogs with acute abdomen syndrome were included in the non-GIFBO control group. The median age was 3.9 years (range, 0.2 to 12.2 years) and median body weight was 20.0 kg (range, 2.1 to 56.0 kg). In this group, 40% (10/25) were spayed females, 36% (9/25) were neutered males, 16% (4/25) were sexually intact females, and 8% (2/25) were sexually intact males. There were 8 mixed-breed dogs, 4 Golden Retrievers, 2 German Shepherd Dogs, and 1 each of Bichon Frise, Dogue de Bordeaux, Miniature Pinscher, Miniature Schnauzer, Newfoundland, American Pit Bull Terrier, Pomeranian, Shar Pei, Shetland Sheepdog, Siberian Husky, and West Highland White Terrier. The median duration of clinical signs prior to presentation was 2 days (range, 1 to 10 days). Clinical signs included vomiting (25/25 [100%]), diarrhea (10/25 [40%]), hyporexia or anorexia (13/25 [52%]), and signs of pain on abdominal palpation (5/25 [20%]).
Initial blood work findings for dogs in the control group were summarized (Table 1). Abdominal ultrasonography did not identify any changes consistent with acute pancreatitis. A definitive diagnosis was made for acute abdomen syndrome in 18 dogs in the control group on the basis of blood work, advanced imaging, and additional procedures that obtained a cytologic or histopathology sample following initial presentation (Table 2). Seven dogs ultimately did not receive a definitive diagnosis; however, presumed diagnoses documented for 4 dogs based on diagnostic results from the time of presentation and initial workup included gastrointestinal ileus, hypoadrenocorticism, parasitism, and vasovagal syncope. In the 3 remaining dogs, altered small intestinal wall layering was identified on ultrasonography but was not further evaluated with biopsy sample acquisition. Each of the dogs lacking a definitive diagnosis improved and were discharged within 48 hours. Additional tests were offered to confirm these presumed diagnoses when appropriate but were either declined due to clinical improvement or the owners declined additional diagnostics or elected to pursue additional diagnostics with their primary veterinarian. None of these dogs returned with recurrence of signs or concern for pancreatitis following hospital discharge.
Results of key variables including point-of-care pancreatic assay screening test results (SNAP cPL test kit; Idexx Laboratories Inc) for client-owned dogs that were treated for acute abdomen syndrome between April 2019 and January 2021 and lacked clinical evidence of acute pancreatitis, grouped on the basis of whether dogs had gastrointestinal foreign body obstruction (GIFBO group; n = 25) versus no GIFBO (control group; 25). All 50 dogs had results available and analyzed for each variable presented. All SNAP cPL tests were performed and interpreted by the primary author (BDL) with results recorded as visually normal or abnormal. Tests were repeated in instances of equivocal results due to indistinguishable control and test spot intensities, and consecutive similar intensities were classified as an abnormal result.
| Variable | GIFBO group (n = 25) | Control group (n = 25) | P value |
|---|---|---|---|
| Age (y) | 5.0 (0.4–13) | 3.9 (0.2–12.2) | 0.59 |
| Body weight (kg) | 19.6 (5.8–46.2) | 20.0 (2.1–56.0) | 0.96 |
| Sex | 0.02 | ||
| No. of males | 19 | 11 | |
| No. of females | 6 | 14 | |
| Duration of clinical signs (d) | 3 (1–21) | 2 (1–10) | 0.01 |
| Laboratory values | |||
| Leukocytes (X 103 cells/μL) | 14,670 (7,400–38,500) | 12,600 (1,300–46,300) | 0.09 |
| Neutrophils (X 103 cells/μL) | 11,390 (4,655–35,420) | 9,072 (208–40,281) | 0.09 |
| Monocytes (X 103 cells/μL) | 809 (380–3,030) | 522 (148–3,392) | 0.12 |
| Thrombocytes (X 103 platelets/μL) | 295 (186–536) | 231 (129–576) | 0.24 |
| Alkaline phosphatase (U/L) | 101 (10–1,476) | 68 (9–3,854) | 0.48 |
| Alanine aminotransferase (U/L) | 63 (11–202) | 57 (20–1,052) | 0.70 |
| BUN (mg/dL) | 13 (5–81) | 16 (7–41) | 0.05 |
| Creatinine (mg/dL) | 0.9 (0.4–1.5) | 0.9 (0.2–3.1) | 0.96 |
| Total protein (g/dL) | 6.4 (4.9–8.0) | 6.5 (2.7–7.5) | 0.59 |
| Albumin (g/dL) | 3.3 ± 0.5) | 3.1 ± 0.6 | 0.17 |
| Globulin (g/dL) | 3.1 (2.0–4.8) | 3.0 (1.0–4.8) | 0.57 |
| No. of abnormal SNAP cPL test results | 3 | 4 | 1.0 |
Normally distributed data expressed as mean ± SD. Nonnormally distributed data expressed as median (range). Values of P < 0.05 are considered significant.
Final diagnoses for signs of acute abdomen syndrome in the 25 dogs of the control group described in Table 1.
| Diagnosis | No. of dogs |
|---|---|
| Gastroenteritis | 2 |
| Acute hemorrhagic diarrheal syndrome | 1 |
| Hypoadrenocorticism | 3 |
| Ileus | 3 |
| Inflammatory bowel disease | 2 |
| Neoplasia | 2 |
| Nonspecific hepatopathy | 1 |
| Parasitism | 1 |
| Gallbladder mucocele | 1 |
| Pyometra | 1 |
| Transiting foreign material | 1 |
| Undetermined | 7 |
| Total | 25 |
GIFBO group
The 25 dogs enrolled in the GIFBO group had a median age of 5.0 years (range, 0.4 to 13.0 years) and a median body weight of 19.6 kg (range, 5.8 to 46.2 kg). The group included 56% (14/25) neutered males, 24% (6/25) spayed females, and 20% (5/25) sexually intact males. There were 9 mixed-breed dogs, 5 Labrador Retrievers, and 1 each of Bernese Mountain Dog, Border Collie, Catahoula, Flat-Coated Retriever, Golden Retriever, Golden Retriever–Poodle cross, Rat Terrier, Shetland Sheepdog, Shih Tzu, Shih Tzu–Bichon Frise cross, and West Highland White Terrier. The median duration of clinical signs prior to presentation was 3 days (range, 1 to 21 days). Clinical signs included vomiting (23/25 [92%]), hyporexia or anorexia (17/25 [ 68%]), signs of pain on abdominal palpation (8/25 [ 32%]), and diarrhea (3/25 [12%]).
Blood work results for dogs in the GIFBO group were summarized (Table 1). Gastrointestinal foreign body obstruction was confirmed by ultrasonography in all dogs prior to surgery. Four of the 25 (16%) dogs were suspected to have had a linear component, and 1 (4%) dog was suspected to have gastrointestinal perforation with associated septic peritonitis.
Intraoperatively, the location of GIFBO included only the small intestinal tract (16/25 [64%]), only the stomach (5/25 [20%]), or a combination of gastric and small intestinal tract (4/25 [16%]; Table 3). The duodenum specifically was affected in 20% (5/25) of dogs. Of the 4 dogs suspected to have had a linear component on abdominal ultrasonography, the linear component was confirmed in just 2 dogs intraoperatively. In 1 dog, the linear obstruction extended from the stomach to the jejunum; the second dog had plication throughout the jejunum with multiple intestinal perforations and associated septic peritonitis. Surgical treatment of GIFBO included a singular enterotomy (16/25 [64%]), gastrotomy (7/25 [28%]), multiple enterotomies (1/25 [4%]), or intestinal resection and anastomosis (1/25 [4%]). No dogs had gross pancreatic changes consistent with acute pancreatitis.
Characteristics of the GIFBO and SNAP cPL results in the 25 dogs of the GIFBO group described in Table 1.
| GIFBO location | No. of dogs with abnormal SNAP cPL results (n = 3) | No. of dogs with normal SNAP cPL results (n = 22) | Total (n = 25) |
|---|---|---|---|
| Discrete foreign body | 3 | 20 | 23 |
| Gastric | 2 | 3 | 5 |
| Gastric and small intestine | 0 | 3 | 3 |
| Small intestine | |||
| Duodenum | 1 | 3 | 4 |
| Jejunum | 0 | 9 | 9 |
| Ileum | 0 | 2 | 2 |
| Linear foreign body | |||
| Gastric and small intestine* | 0 | 1 | 1 |
| Small intestine | |||
| Duodenum | 0 | 0 | 0 |
| Jejunum | 0 | 1 | 1 |
| Ileum | 0 | 0 | 0 |
*Multiple small intestinal segments affected.
See Table 1 for rest of key.
SNAP cPL test results
Overall, 7 of the 50 (14%) dogs had an abnormal SNAP cPL test result, with 4 abnormal results in the non-GIFBO control group and 3 abnormal results in the GIFBO group. A post hoc power analysis indicated that 517 dogs in each group would be required to establish significant differences at these initial proportions, so study enrollment was concluded at 25 dogs in each group. Final diagnoses for dogs with abnormal SNAP cPL test results included gastric foreign body (n = 2) and 1 each of duodenal foreign body, gastroenteritis, ileus, and inflammatory bowel disease; 1 dog did not receive a definitive diagnosis. There was no significant difference in SNAP cPL test results between groups (Table 1). No significant differences in SNAP test results were identified within the GIFBO group on the basis of the obstruction type (linear vs discrete) or location (duodenum vs other; Table 3).
The only significant differences between the 2 groups were sex (P = 0.02) and duration of clinical signs (P = 0.01), with the GIFBO group having had a higher proportion of male dogs and a slightly longer duration of clinical signs prior to presentation (Table 1). Neither of these findings were considered to be clinically relevant regarding SNAP cPL test results. The combined population was analyzed for clinical association with abnormal SNAP cPL test results (Table 4). Older patient age was significantly (P = 0.01) associated with an abnormal SNAP cPL test result. No other variables were associated with test results.
Comparison of population variables for all 50 dogs described in Table 1, grouped on the basis of whether dogs had an abnormal versus normal SNAP cPL test result.
| Variable | Dogs with abnormal SNAP cPL results (n = 7) | Dogs with normal SNAP cPL results (n = 43) | P value |
|---|---|---|---|
| Age (y) | 9.0 (1.0–11.4) | 4.0 (0.25–13.0) | 0.01 |
| Body weight (kg) | 27.3 (4.3–41.8) | 15.7 (2.1–56.0) | 0.52 |
| Sex | 0.87 | ||
| No. of males | 4 | 26 | |
| No. of females | 3 | 17 | |
| Duration of clinical signs (d) | 2 (1–21) | 2 (1–14) | 0.71 |
| Laboratory values | |||
| Leukocytes (X 103 cells/μL) | 14,550 (9,010–21,090) | 13,390 (1,300–46,300) | 0.78 |
| Neutrophils (X 103 cells/μL) | 11,169 (6,834–6,940) | 10,815 (208–40,281) | 0.66 |
| Monocytes (X 103 cells/μL) | 918 (320–1,887) | 649 (148–3,392) | 0.38 |
| Thrombocytes (X 103 platelets/μL) | 271 (194–507) | 284 (129–576) | 0.82 |
| Alkaline phosphatase (U/L) | 94 (21–327) | 69 (9–3,854) | 0.72 |
| Alanine aminotransferase (U/L) | 57 (16–190) | 63 (11–1,052) | 0.96 |
| BUN (mg/dL) | 13 (6–26) | 15 (5–81) | 0.65 |
| Creatinine (mg/dL) | 0.9 (0.5–1.2) | 0.9 (0.2–3.1) | 0.56 |
| Total protein (g/dL) | 6.5 (4.7–7.7) | 6.4 (2.7–8.0) | 0.90 |
| Albumin (g/dL) | 3.0 ± 0.4 | 3.2 ± 0.5 | 0.12 |
| Globulin (g/dL) | 3.1 (2.2–4.8) | 3.0 (1.0–4.8) | 0.57 |
See Table 1 for key.
Discussion
To our knowledge, the present study was the first to specifically evaluate SNAP cPL test results in a canine GIFBO population and assess whether abnormal test results are more common in dogs with GIFBO, compared with dogs without GIFBO. An abnormal SNAP cPL test result was found in only 12% (3/25) of dogs in the GIFBO group, which did not significantly differ from the non-GIFBO control group (4/25 [16%]). On the basis of these findings, we rejected our initial hypothesis.
Previous studies evaluating the accuracy of SNAP cPL tests have reported abnormal results in up to 42.9% (3/7) of dogs with GIFBO.1 Our study indicated a much lower frequency of abnormal SNAP cPL test results in dogs with GIFBO. The explanation for this difference is likely multifactorial and could be related to the larger sample size here compared to previous studies, differences in study design (ie, prospective vs retrospective), the exclusion of dogs exhibiting diagnostic results suggestive of pancreatitis, and the ability and consistency of the ultrasonographer in identifying changes suggestive of acute pancreatitis. Our results indicated that SNAP cPL tests are more accurate in cases of GIFBO than previously thought. That said, cautious interpretation of any abnormal SNAP cPL test result is warranted. Clinicians should remain cognizant that the SNAP cPL test was created as an initial screening test and any abnormal findings should be validated with further diagnostics. The 12% (3/25) of abnormal SNAP test results reported here supported the recommendation for advanced imaging for all dogs suspected of having acute pancreatitis. The individual dogs in the GIFBO group with abnormal SNAP test results may have had delayed identification of surgical disease under different circumstances, which could have substantially impacted patient morbidity and death.3,4
Of the dogs in the non-GIFBO control group, only those with small intestinal disease had abnormal SNAP cPL tests. The mechanism for why particular dogs in the GIFBO and non-GIFBO groups had abnormal SNAP cPL test results could have been similar. Underlying gastrointestinal pathology could cause alterations in pancreatic enzyme concentrations, as several studies1,8–10 have found associations between nonpancreatic diseases and high Spec cPL results. In a model using rodents, the presence of a neural crosstalk has been reported whereby stimulation of the duodenum via intraduodenal toxins can induce acute pancreatitis without significant elevations in amylase or lipase as a result of neurogenic inflammation.11 The possibility for such an intimate relationship between stimulation of the upper gastrointestinal tract and pancreatic inflammation suggests that GIFBOs or other forms of small intestinal disease may be able to produce abnormal pancreatic assay results with ultrasonographically normal pancreatic findings, as reported here. An example of this can be found in cases of gastric dilatation-volvulus. A study by Spinella et al12 showed high canine pancreatic lipase immunoreactivity (cPLI) values in patients with gastric dilatation-volvulus and demonstrated associations between high cPLI values and worsened outcome. Five of the dogs in the GIFBO group had conditions that involved duodenal segments; however, only one of these dogs had an abnormal SNAP cPL test result. These findings suggested that physical obstruction of the duodenum alone was unlikely to have induced pancreatitis via secondary effects to the pancreatic ducts; however, more study is warranted. Ultimately, further studies are needed to elucidate the influence of primary gastrointestinal disease on pancreatic enzyme levels and the validity of pancreatic screening tests in patients with multiple concurrent disease processes.
The primary significant finding in the present study was an association between older patient age and abnormal SNAP cPL test results. It may be possible that older dogs with upper gastrointestinal disease are more likely to demonstrate the aforementioned changes with respect to pancreatic enzymes than their younger counterparts. However, presently there is no literature establishing a specific association between age and pancreatic assay results.
In the present study, patients were considered ineligible if acute pancreatitis was suspected on the basis of blood work and abdominal ultrasonographic findings. Abdominal ultrasonography is currently considered the imaging modality of choice in diagnosing acute pancreatitis.13 A study by Cridge et al8 found that abdominal ultrasonographic findings are moderately correlated with the clinical diagnosis of acute pancreatitis. Individual ultrasonographic changes to the pancreas suggestive of acute pancreatitis included enlargement or irregularity of the organ, regions of hypoechoic echogenicity within the tissue, hyperechoic peripancreatic fat and mesentery, and peripancreatic peritoneal effusion. If just one of these abnormalities was identified and used to make the diagnosis of pancreatitis via ultrasonography, the sensitivity was reported as 89%, whereas if multiple criteria were required, a sensitivity as low as 43% was reported.8 We evaluated for these same abnormalities and excluded dogs with any of these described pancreatic or peripancreatic ultrasonographic changes. Peritoneal effusion was present in 10% (5/50) of dogs in the present study despite being listed as a supporting factor for pancreatitis. Four of these 5 dogs were in the GIFBO group, and effusion was scant and considered secondary to gastrointestinal tract inflammation, with the finding in 1 dog confirmed as septic peritonitis. Intraoperative gross pancreatic evaluation was subjectively normal in all 4 of these dogs. The single dog in the control group exhibiting peritoneal effusion was confirmed to have had hemoperitoneum, and no abnormalities were identified on ultrasonographic evaluation of the pancreas. Prospective pancreatic evaluation by a single experienced board-certified veterinary radiologist provided consistency across all cases.
Historically, high amylase and lipase concentrations have been used to aid in diagnosing pancreatitis. It has since been revealed that measurements of amylase and lipase alone have limited clinical value.5,13 Given the unpredictability of hematologic parameters, several tests have consequently been developed to aid in the diagnosis of acute pancreatitis. The cPLI test measures lipase molecules of solely pancreatic acinar cell origin and is currently the clinicopathologic test of choice for diagnosing pancreatitis.1,6,13,14 The Spec cPL test provides a quantitative cPL value from which cutoff values can be established for diagnostic purposes. Reported sensitivity and specificity for Spec cPL vary from 70.0% to 90.9% and 74.1% to 100%, respectively.1,5,6,15 A major limitation of the Spec cPL test is that it must be sent to an outside laboratory, requires additional time (24 to 72 hours) to obtain results, and may be more costly than other tests.6 The SNAP cPL test was developed in response to these limitations, providing a rapid point-of-care semiquantitative test that would allow general practitioners to obtain results within 10 minutes. Comparison of SNAP cPL and Spec cPL results has revealed good agreement with one another in cases with ultrasonographically confirmed acute pancreatitis.1 However, each test has poor agreement overall with the diagnosis of acute pancreatitis in a large population of dogs with acute abdomen syndrome due predominately to false-positive test results.1 The present study found that 14% (7/50) of overall subjects had an abnormal SNAP cPL test result that could have led to the misdiagnosis of acute pancreatitis. This again highlighted the need for multiple diagnostic modalities (ie, abdominal imaging and biochemical tests) to be utilized in cases of suspected pancreatitis and that reliance on any singular cPL test risks a false-positive result.
There were several limitations to be considered in the present study. A primary limitation was the inherent difficulty in definitively diagnosing acute pancreatitis. Histopathology would represent the gold standard to diagnose and characterize pancreatic inflammation but is impractical in the clinical setting.2,5,6,13 In the present study, histopathology was not part of the study criteria for dogs in the GIFBO group, as biopsy was considered a risk for inducing additional patient morbidity (ie, pancreatitis) in an already clinically compromised canine population. Even more, it has been reported for lesions to be missed on pancreatic biopsy or for histologic reports to fail to identify inflammation or necrosis in patients with grossly abnormal tissue.1,2,6 Acute pancreatitis is typically diagnosed through careful examination of a patient’s clinical presentation, physical examination findings, blood work including various enzyme assays, and diagnostic imaging, as previously discussed. The criteria established in the design of our study were meant to eliminate inclusion of patients affected by primary acute pancreatitis; however, inclusion of a dog with subclinical pancreatitis still could not have been completely ruled out due to inherent challenges with the diagnosis of this disease.
We did not require Spec cPL tests for patients in the present study, which may be a consideration for future studies. Spec and SNAP cPL tests have shown good agreement with each other in cases of acute pancreatitis, and our goal was not to evaluate Spec cPL results in cases of GIFBO. Our primary goal was to assess the SNAP cPL test, as this rapid test is more likely to be used by general practitioners and the perceived limitations, such as a high proportion of abnormal results in cases of GIFBO, require thorough investigation to guide practitioners in test interpretation. It may have been interesting to correlate Spec cPL values in those cases with abnormal SNAP cPL results. That said, in the clinical setting the Spec cPL test still requires time for results to become available and delay can be detrimental to patients with surgical conditions. The authors of this report advocate for abdominal ultrasonography to be utilized as the follow-up diagnostic for patients from which an abnormal SNAP cPL test result is obtained, consistent with the manufacturer recommendations.
Operator error in running the SNAP cPL tests was unlikely to influence results, as all instructions were followed as provided by the manufacturer. Prolonged storage of samples was unlikely to contribute to error, as all samples were refrigerated at 4 °C and tested within 7 days, and previous research demonstrates stability of cPLI concentrations for up to 21 days when kept at room temperature, refrigerated, or frozen.16
The sample size of each group included 25 prospectively enrolled dogs. This sample size may seem limited, but it was still more than triple the sample size of a previous study1 reporting abnormal SNAP cPL results in 42.9% (3/7) of dogs with GIFBO.1 A post hoc power analysis supported that it would have been impractical to enroll the number of dogs required to establish a significant difference in SNAP cPL results between the GIFBO and non-GIFBO groups.
In conclusion, SNAP cPL test results appeared to have been more accurate in dogs with GIFBO in the present study than previously suggested. That said, an abnormal SNAP cPL test result should still be interpreted with caution, and confirmation with abdominal ultrasonography is warranted consistent with manufacturer recommendations on the basis of the fact that 12% (3/25) of dogs with GIFBO had abnormal SNAP cPL test results in the present study. This may be of particular importance in older dogs, which, on the basis of our findings, may be more likely to have an abnormal SNAP cPL result when a gastrointestinal disease process other than acute pancreatitis is present.
Acknowledgments
This work was supported by the BluePearl Veterinary Partners Study Design and Review Committee. Funding sources did not have any involvement in the data analysis and interpretation or writing and publication of this manuscript.
The authors declare that there were no conflicts of interest.
The authors thank Erik H. Hofmeister for his contributions to our study.
References
- 1. ↑
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- 2. ↑
Chartier MA, Hill SL, Sunico S, Suchodolski JS, Robertson JE, Steiner JM. Pancreas-specific lipase concentrations and amylase and lipase activities in the peritoneal fluid of dogs with suspected pancreatitis. Vet J. 2014;201(3):385–389. doi:10.1016/j.tvjl.2014.07.014
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Suggested guidelines for suspected canine pancreatitis. Idexx Laboratories Inc. Accessed February 5, 2021. https://www.idexx.com/en/veterinary/snap-tests/snap-cpl-test/?utm_source=vanity_url&utm_medium=multi&utm_campaign=na&utm_content=snapcpl
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Cridge H, Sullivant AM, Wills RW, Lee AM. Association between abdominal ultrasound findings, the specific canine pancreatic lipase assay, clinical severity indices, and clinical diagnosis in dogs with pancreatitis. J Vet Intern Med. 2020;34(2):636–643. doi:10.1111/jvim.15693
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Mawby DI, Whittemore JC, Fecteau KA. Canine pancreatic-specific lipase concentrations in clinically healthy dogs and dogs with naturally occurring hyperadrenocorticism. J Vet Intern Med. 2014;28(4):1244–1250. doi:10.1111/jvim.12376
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