An immunoturbidimetric assay for canine C-reactive protein

Antiserum was raised in sheep against canine C-reactive protein (CRP) and antibody, which was not specific for CRP, was removed by absorption with normal canine serum protein linked to agarose beads. The antiserum was used to develop an immunoturbidimetric assay for canine CRP on a MIRA (Roche Diagnostics) automated clinical biochemical analyser and assessed for routine analysis of CRP in canine serum samples. The assay gave standard curves with each standard having a coefficient of variance (CV) between 4.8 and 11%, interassay CVs below 11% and intra-assay CVs of less than 5%. Parallel dilution curves were obtained with purified CRP diluted in buffer and with endogenous CRP in serum diluted with buffer or with a serum with a negligible CRP content. The immunoturbidimetric assay results correlated with the results obtained using an ELISA method, r=0.88. The immunoturbidimetric assay of canine CRP proved to be suitable for the routine analysis of canine CRP.     

Changes in serum C-reactive protein levels in dogs with various disorders and surgical traumas

The serum levels of C-reactive protein (CRP) produced as an inflammatory response in dogs with various disorders and surgical traumas were measured by enzyme-linked immunoabsorbent assay and slide reversed passive latex agglutination test (RPLA). The CRP levels were greatly increased 1–2 days after surgery in most of the dogs (n=29) subjected to surgery. These levels had markedly decreased by the time the sutures were removed. In dogs with various disorders (n=58), the serum CRP levels at first diagnosis were high in infectious diseases. In dogs from which paired serum samples were examined, the serum CRP usually showed a decrease with improvement in the condition (n=11) or a terminal increase (n=4) but, conversely, some showed an increase with improvement in the condition (n=3).Abbreviations CRP C-reactive protein - ELISA enzyme-linked immunoabsorbent assay - Latex soap free latex - RPLA reversed passive latex agglutination     

Evaluation of a point-of-care test for canine C-reactive protein

Background: In veterinary medicine, there is increasing interest in measuring C‐reactive protein (CRP) as a tool for diagnosis and monitoring of inflammatory diseases. Reported CRP concentrations for healthy dogs have ranged from 0 to 8.9 mg/L. Objectives: The aims of this study were to evaluate a canine‐specific point‐of‐care (POC) lateral flow immunoassay for qualitative CRP measurement in healthy and diseased dogs and to compare results with those obtained by a quantitative ELISA. Methods: Blood samples from 73 client‐owned dogs were available for testing: 16 healthy dogs and 57 dogs with a variety of infectious, inflammatory, or neoplastic diseases. CRP was measured in heparinized whole blood samples and serum with the TECOmedical Dog CRP‐visual POC test. A red line develops in the POC device if CRP is ≥5 mg/L, and results are scored as negative or positive. An ELISA validated previously for canine serum was used as the reference method. Results: For all dogs, serum CRP concentrations measured by the ELISA ranged from 0.1 to ≥350 mg/L (median=38 mg/L). Percentages of the CRP POC test results that agreed with the ELISA results were 98.6% for whole blood and 97.3% for serum samples. For serum samples, sensitivity of the POC test was 96.4% and specificity was 81.3%. For whole blood, sensitivity was 94.7% and specificity was 93.8%. Conclusions: The POC test had very good agreement with the ELISA test and had high sensitivity and specificity; therefore, it can be used as a qualitative test to screen for increases in CRP concentrations.     

Use of C-reactive protein to predict outcome in dogs with systemic inflammatory response syndrome or sepsis

Background – There is a high mortality rate in patients with systemic inflammatory response syndrome (SIRS) or sepsis. Therefore, an early diagnosis and prognostic assessment is important for optimal therapeutic intervention. The objective of the study was to evaluate if baseline values and changes in serum C-reactive protein (CRP) might predict survival in dogs with SIRS and sepsis.
Design – Prospective study; July 2004 to July 2005.
Setting – Small Animal Clinic, Berlin, Clinic of Small Animal Medicine, Munich.
Animals – Sixty-one dogs.
Measurements and Main Results – For the CRP analysis blood was drawn on day 0, 1, and 2; CRP was measured using a commercial ELISA test kit. Thirteen dogs suffered from nonseptic SIRS and 48 dogs from sepsis. The 14-day survival rate was 61% (69% nonseptic SIRS, 58% sepsis). Serum CRP was higher in sick dogs compared with controls ( P <0.001). Over the 3-day period surviving dogs ( n =31) displayed a significantly greater decrease in CRP than nonsurvivors ( n =10) ( P =0.001). No correlation was found between the initial CRP concentrations and the survival rate. The changes in CRP corresponded to the survival rate ( P =0.01).
Conclusion – There was no significant relationship between the survival rate in dogs with nonseptic SIRS or sepsis and the initial serum CRP concentrations. There was a correlation between decreasing CRP concentrations and recovery from disease. However, the changes in CRP concentrations over a 3-day period correctly predicted survival in 94% of dogs and death in 30% of the dogs (false positive rate 22%).     

Serum C-reactive protein concentrations in healthy Miniature Schnauzer dogs

Background: C‐reactive protein (CRP) is a sensitive marker for inflammation in people and dogs. In people, an association between CRP concentration and atherosclerosis has been reported. Atherosclerosis is rare in dogs, but the Miniature Schnauzer breed may be at increased risk for developing this vascular disease. It is not known if CRP concentrations in Miniature Schnauzer dogs differ from those in other dog breeds. Objectives: Our objectives were to validate an automated human CRP assay for measuring CRP in dogs and compare CRP concentrations in healthy Miniature Schnauzer dogs with those in non‐Miniature Schnauzer breeds. Methods: Sera from 37 non‐Miniature Schnauzer dogs with inflammatory disease were pooled and used to validate a human CRP immunoturbidimetric assay for measuring canine CRP. Blood was collected from 20 healthy Miniature Schnauzer dogs and 41 healthy dogs of other breeds. Median serum CRP concentration of healthy Miniature Schnauzer dogs was compared with that of healthy non‐Miniature Schnauzer dogs. Results: The human CRP assay measured CRP reliably with linearity between 0 and 20 mg/L. CRP concentration for healthy Miniature Schnauzer dogs (median 4.0 mg/L, minimum–maximum 0–18.2 mg/L) was significantly higher than for the healthy non‐Miniature Schnauzer dogs (median 0.1 mg/L, minimum–maximum 0–10.7 mg/L); 17 of the 20 Miniature Schnauzer dogs had values that overlapped with those of the non‐Miniature Schnauzer dogs. Conclusions: Median CRP concentration of Miniature Schnauzer dogs was slightly higher than that of other breeds of dogs. A relationship between higher CRP concentration in Miniature Schnauzer dogs and idiopathic hyperlipidemia, pancreatitis, and possible increased risk for atherosclerosis remains to be determined.     

Serum acute phase protein concentrations in dogs with hyperadrenocorticism with and without concurrent inflammatory conditions

Background: Acute phase proteins (APPs) are promising markers of inflammation in dogs, because they are more sensitive than WBC counts in detecting clinical and subclinical inflammation. Endogenous corticosteroids can mask an acute phase response and make it more difficult to identify underlying inflammatory disease. Objective: The purpose of this study was to evaluate the acute phase protein response in dogs with spontaneous hyperadrenocorticism (HAC) with and without concurrent inflammatory conditions. Methods: Serum concentrations of C‐reactive protein (CRP), haptoglobin (Hp), fibrinogen, and albumin were measured in 44 healthy adult dogs and 39 dogs with HAC; the HAC group was further divided into dogs with and without concurrent infection/inflammation. A fourth group of dogs with severe sepsis and without HAC was compared with the dogs with HAC and severe sepsis. Results: Dogs with uncomplicated HAC had significantly higher Hp and fibrinogen concentrations compared with healthy control dogs (P<.001). Dogs with HAC and severe inflammatory disease also had significantly higher CRP and lower albumin concentrations than control dogs and dogs with HAC without concurrent inflammation. Dogs with sepsis but without HAC had significantly higher CRP concentrations than dogs with HAC and sepsis. Conclusions: Dogs with HAC had increases in the moderate APPs (Hp and fibrinogen), and no significant changes in CRP and albumin compared with healthy dogs. Although concurrent HAC appeared to blunt the CRP response in dogs with sepsis, increased serum CRP concentration in dogs with HAC is likely indicative of severe concurrent inflammation.     

Physiological levels of C-reactive protein in normal canine sera

This study was undertaken to investigate whether the level of C-reactive protein (CRP) in the serum of dogs undergoes physiological variation, using 10 normal Beagle dogs (5 males and 5 females), 1–2 years old, maintained in a healthy condition in a controlled environment. The CRP concentration in the sera collected seven times each day at intervals of approximately 3 h ranged from 0.8 to 16.4 µg/ml (mean 5.06±3.60) in one experiment and from 0.8 to 14.0 µg/ml (mean 4.50±2.80) in a second experiment. On examining the 24-h variations in the concentration of CRP in serum, neither consistent changes nor a definite pattern of circadian rhythm was detected. During 28 days observation, only very slight changes, which seemed attributable to analytical errors, were seen in any of the dogs, except one. The concentration of CRP in the serum during the 28 days ranged from 0.8 to 22.6 µg/ml (mean 3.65±1.40). The concentrations underwent no significant variations in individual dogs, but significant differences were found between the dogs (p<0.01).     

C-reactive protein, tumor necrosis factor α, and interleukin-6 in dogs with pyometra and SIRS

Objective: To determine the frequency of the systemic inflammatory response syndrome (SIRS) in canine pyometra and to evaluate the relationship between C‐reactive protein (CRP), tumor necrosis factor α (TNFα), interleukin‐6 (IL‐6), and SIRS. Design: Prospective clinical study. Setting: Veterinary teaching hospital. Animals: Fifty‐three clinical cases of canine pyometra and 19 healthy control bitches. Interventions: Upon admission to the veterinary hospital, history and physical examination findings, including previously defined clinical SIRS parameters, were documented. Blood samples were obtained for hematology and biochemical tests and for CRP, TNFα, and IL‐6 analysis. The diagnosis of pyometra was confirmed by histopathology of the uterus after ovariohysterectomy. After surgery, clinical SIRS parameters, length of hospitalization, and mortality were recorded. Measurements and main results: Pyometra dogs were grouped as SIRS positive (30/53; 57%) or SIRS negative (23/53; 43%). Logistic regression showed that CRP was the only parameter that significantly related to SIRS apart from the clinical criteria that define this syndrome. The mortality rate was low (2/53; 3.8%), and conclusions regarding association with SIRS could not be drawn. A positive SIRS status, high plasma CRP concentration, and high body temperature were variables that related to increased morbidity reflected by the length of hospitalization. Conclusions: SIRS was seen in 57% of canine pyometra cases and a positive SIRS status showed a positive association with prolonged hospitalization. The mortality rate was low (3.3%) among SIRS positive dogs, indicating that progression to multiple organ dysfunction syndrome (MODS) rarely occurs in surgically treated cases of pyometra. CRP was associated with SIRS and with prolonged hospitalization. Further studies of plasma CRP may be warranted in canine intensive care cases susceptible to development of SIRS and MODS.