C‐reactive protein concentration in dogs with primary immune‐mediated hemolytic anemia

Background: Canine primary immune-mediated hemolytic anemia (IMHA) is associated with a high-mortality rate. C-reactive protein (CRP) is the most important acute-phase protein in dogs and may have value as a marker of prognosis or response to treatment in IMHA. Objective: The objectives of this study were to evaluate serum CRP concentration in dogs with primary IMHA at presentation and during treatment, to assess potential differences based on survival time, and to compare CRP with other laboratory parameters of inflammation and prognosis. Methods: Inclusion criteria for primary IMHA were anemia (PCV<0.30 L/L), a positive Coombs' test or persistent autoagglutination of erythrocytes, and the exclusion of underlying diseases by other diagnostic tests. Dogs were divided into 2 groups based on survival: dogs that were still alive 14 days after start of treatment (group 1) and dogs that died or were euthanized before day 14 (group 2). Serum CRP concentration, a CBC, and a biochemistry profile were performed on days 0, 3, 8, and 14. Serum CRP also was determined in 25 clinically healthy dogs. Results: CRP concentration in the 25 clinically healthy dogs ranged from 0–8.9 μg/mL (median 2.2 μg/mL). Thirty dogs were diagnosed with primary IMHA, 24 in group 1 and 6 in group 2. On day 0, CRP concentration in dogs in both groups (median 224 μg/mL) was increased above the reference interval. In group 1 dogs, median CRP concentration was 242 μg/mL on day 0, 69 μg/mL on day 3, 35 μg/mL on day 8, and 2 μg/mL on day 14. In group 2 dogs, median CRP concentration was 194 μg/mL on day 0, 119 μg/mL on day 3, and 41 μg/mL on day 8; only 1 dog in group 2 survived to day 8. There was a significant correlation between CRP and total WBC concentrations on days 0 and 3 (r=−.598, P=.003). Conclusions: Serum CRP concentration was markedly increased in dogs with primary IMHA. CRP concentration did not differ based on patient survival, but might be a marker for long-term monitoring of these patients.     

Evaluation of serum haptoglobin and C‐reactive protein in dogs with mammary tumors

Background: In veterinary medicine, there is increasing interest in measuring acute phase proteins as a tool in the diagnosis and monitoring of neoplastic diseases. Although mammary neoplasms are the most common type of cancer in dogs, acute phase proteins have not been extensively evaluated in dogs with mammary tumors. Objectives: The aim of this study was to evaluate serum haptoglobin (Hp) and C‐reactive protein (CRP) concentrations in the dogs with mammary tumors and assess their potential association with malignancy. Methods: A retrospective study of dogs with mammary tumors was performed. Serum concentrations of CRP and Hp were determined in healthy control dogs (n=20) and dogs with mammary tumors before surgery (n=41). Mammary tumors were grouped as carcinomas (n=24), fibrosarcoma (n=1), malignant mixed tumors (n=7), benign mixed tumors (n=6), and adenomas (n=3). CRP and Hp concentrations were compared in dogs with different tumor types and were also compared based on tumor size, lymph node infiltration, skin ulceration, fixation to underlying tissue, and time between tumor identification and removal. Results: Hp concentration was significantly (P<.043) higher in dogs with mammary tumors (median 2.03 g/L, range 0.09–2.94 g/L) compared with controls (1.38 g/L, range 0.08–3.00 g/L), but the range of values overlapped considerably. CRP concentration was higher in dogs with carcinomas (4.70 mg/L, range 0.63–128.96 mg/L) vs controls (2.11 mg/L, range 0.25–6.57 mg/L) (P=.0008) and in dogs with ulcerated skin (14.8 mg/L, range 5.7–128.9 mg/L, n=3) compared with those without ulceration (2.4 mg/L, range 0.11–30.3 mg/L, n=38) (P=.048). Conclusions: Serum Hp and CRP do not appear to have value in diagnosing or predicting malignancy of mammary tumors in dogs. Higher CRP concentrations in dogs with mammary carcinoma suggest a role for inflammation in this tumor type.     

Extracellular cyclic adenosine monophosphate‐dependent protein kinase A autoantibody and C‐reactive protein as serum biomarkers for diagnosis of cancer in dogs

Protein kinase A, a cyclic adenosine monophosphate (AMP)‐dependent enzyme, normally exists within mammalian cells; however, in cancer cells, it can leak out and be found in the serum. Extracellular cyclic AMP‐dependent protein kinase A (ECPKA) has been determined to increase in the serum of cancer‐bearing dogs. However, there have been no reports in the veterinary literature on serum ECPKA autoantibody (ECPKA‐Ab) expression in dogs with cancer. The aim of this study was to evaluate ECPKA‐Ab and C‐reactive protein (CRP) as serum biomarkers for cancer in dogs. ECPKA‐Ab and CRP levels were detected by an enzyme‐linked immunosorbent assay in serum samples from dogs with malignant tumours (n = 167), benign tumours (n = 42), or non‐tumour disease (n = 155) and from healthy control dogs (n = 123). ECPKA‐Ab and CRP levels were significantly higher in the dogs with malignant tumours than in those with benign tumours or non‐tumour diseases, as well as in the healthy controls (P < 0.001, Kruskal‐Wallis test). There was a significant positive correlation between the neoplastic index, which was developed using ECPKA‐Ab and CRP levels, and the presence of cancer in dogs (P < 0.001); the area under the receiver‐operating characteristic curve was estimated to be >0.85 (P < 0.001). In conclusion, ECPKA‐Ab is a potential serum biomarker for a broad spectrum of cancers. Combined measurement of CRP and ECPKA‐Ab levels in serum improves the sensitivity and accuracy of a diagnosis of cancer in dogs.     

Comparison of paired serum and lithium heparin plasma samples for the measurement of serum amyloid A in horses using an automated turbidimetric immunoassay

This study aimed to evaluate whether equine serum amyloid A (SAA) concentrations could be reliably measured in plasma with a turbidimetric immunoassay previously validated for equine SAA concentrations in serum. Paired serum and lithium-heparin samples obtained from 40 horses were evaluated. No difference was found in SAA concentrations between serum and plasma using a paired t test (P = 0.48). The correlation between paired samples was 0.97 (Spearman’s rank P < 0.0001; 95% confidence interval 0.95–0.99). Passing-Bablok regression analyses revealed no differences between paired samples. Bland–Altman plots revealed a positive bias in plasma compared to serum but the difference was not considered clinically significant. The results indicate that lithium-heparin plasma samples are suitable for measurement of equine SAA using this method. Use of either serum or plasma allows for greater flexibility when it comes to sample collection although care should be taken when comparing data between measurements from different sample types.     

Plasma C‐Reactive Protein and Haptoglobin Concentrations in Critically Ill Neonatal Foals

Background

Accurate diagnostic markers for sepsis in neonatal foals are needed. Plasma C‐reactive protein concentration (p[CRP]) and haptoglobin concentration (p[Hp]) are well‐established biomarkers of infection in humans, but studies are lacking in foals.

Hypotheses

p[CRP]) and p[Hp] are increased in septic foals compared to sick nonseptic and healthy control foals, and are predictive of survival.

Animals

Eighty critically ill foals (40 septic, 40 sick nonseptic) and 39 healthy control foals <1 week of age.

Methods

Multicenter, prospective observational clinical study. Venous blood was collected at admission from septic and sick nonseptic foals and from clinically healthy foals at 24 h of age. A diagnosis of sepsis was made based on positive blood culture or a sepsis score >11, and p[CRP] and p[Hp] were measured by using ELISA tests. Data were analyzed by using the Mann‐Whitney U‐test and forward stepwise multivariable linear regression. P < .05 was considered significant.

Results

Plasma [CRP] was positively associated with age, serum globulin, adrenomedullin, and bilirubin concentrations, aspartate aminotransferase activity, glutamyl‐transferase activity, band neutrophil count, and rectal temperature, and was increased in foals with toxic neutrophils, enterocolitis, colic, rib fractures and septic arthritis. Surprisingly, p[Hp] was lower in septic foals than in sick nonseptic foals. Neither p[CRP] or p[Hp] was predictive of survival in critically ill foals.

Conclusions and Clinical Importance

Plasma [CRP] increases with inflammation in neonatal foals but is not indicative of sepsis. Single time point, admission sampling of p[CRP] and p[Hp] do not appear to be useful biomarkers for sepsis in foals.     

Evaluation of a commercially available human C-reactive protein (CRP) turbidometric immunoassay for determination of canine serum CRP concentration

Background: Serum C-reactive protein (CRP) is an acute phase marker in dogs that is useful for the diagnosis and monitoring of inflammatory disease. Rapid, reliable, and automated assays are preferable for routine evaluation of canine serum CRP concentration.
Objective: The aim of this study was to evaluate whether canine serum CRP concentration could be measured reliably using an automated turbidometric immunoassay (TIA) designed for use with human serum.
Methods: A commercially available TIA for human serum CRP (Bayer, Newbury, UK) was used to measure canine serum CRP concentration. Cross-reactivity of antigen was evaluated by the Ouchterlony procedure. Intra-and interassay imprecision was investigated by multiple measurements on canine serum samples and serum pools, respectively. Assay inaccuracy was investigated by linearity under dilution and comparison of methodologies (canine CRP ELISA, Tridelta Development Ltd, Kildare, UK). Then the assay was applied to serum samples from 14 clinically healthy dogs, 11 dogs with neoplasia, 13 with infections, 8 with endocrine or metabolic diseases, and 10 with miscellaneous diseases.
Results: Cross-reactivity between canine serum CRP and the anti-human CRP antibody was found. Intra-and interassay imprecision ranged from 5.2% to 10.8% and 3.0% to 10.2%, respectively. Serum CRP concentration was measured in a linear and proportional manner. There was no significant disagreement and there was linear correlation of the results in the comparison of methodologies, except for a slight proportional discrepancy at low CRP concentrations (<10 μg/mL). Dogs with infections had a significantly higher concentration of serum CRP than did all other dogs, and dogs with neoplasia had a significantly higher concentration of serum CRP than did clinically healthy dogs.
Conclusions: Canine serum CRP concentration can be measured reliably using the commercially available TIA designed for human CRP.     

Internal quality control of a turbidimetric immunoassay for canine serum C-reactive protein based on pooled patient samples

BACKGROUND: Optimized internal quality control (IQC) procedures are important to ensure that only results without medically important errors are used for medical decision-making and to ensure that unnecessary rejection of valid analytical runs is avoided. Additionally, estimates of the analytical performance can be derived from IQC data. In the absence of available species-specific standards of a compound, the use of alternative control materials based on patient samples is a possibility, although investigations on the suitability of this approach are needed. OBJECTIVES: The objective of the study was to plan and implement a simple IQC procedure with control material based on pooled canine serum samples for a turbidimetric immunoassay (TIA) for the determination of human C-reactive protein (CRP) that recently was validated for the determination of canine serum CRP, and to assess the clinical analytical performance of the assay. METHODS: Proposed guidelines for the planning and implementation of IQC procedures were followed by using 2 control materials. Quality requirements of the assay were defined objectively by means of available data on biological variation, and goals for IQC performance were defined according to recommendations (probability of error detection [P(ed)] >.90 and of false rejection [P(fr)] <.05). Analytical performance was evaluated by means of medical decision charts. RESULTS: The control rule of 1(2.5s) (ie, rejection of the analytical run if at least 1 of 2 control materials deviates from the mean by more than 2.5 SD) fulfilled the criteria of predicted IQC performance (P(ed) =.94-1.00, P(fr) =.03). The IQC method was successfully implemented over a 14-week period. The observed coefficient of variation in the period of monitoring was 3.8% (low) and 2.9% (high), which equals excellent analytical performance. CONCLUSIONS: It was possible to plan and implement a simple IQC procedure for the CRP-TIA with control materials based on canine serum samples that fulfilled the criteria of high error detection and low false rejection of valid analytical runs. The assay showed excellent long-term analytical performance over a 14-week period.     

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.     

Comparison of Oral Prednisone and Prednisone Combined with Metronidazole for Induction Therapy of Canine Inflammatory Bowel Disease: A Randomized‐Controlled Trial

Background: Although prednisone and metronidazole are commonly used to treat canine inflammatory bowel disease (IBD), no randomized‐controlled trials have been performed. Hypothesis: Combination drug therapy with prednisone and metronidazole will be more effective than prednisone alone for treatment of canine IBD. Reduction in disease severity will be accompanied by decreased canine IBD activity index (CIBDAI) scores and serum C‐reactive protein (CRP) concentrations. Animals: Fifty‐four pet dogs diagnosed with IBD of varying severity. Methods: Dogs were randomized to receive oral prednisone (1 mg/kg; n = 25) or prednisone and metronidazole (10 mg/kg; n = 29) twice daily for 21 days. Clinical (CIBDAI) scores and serum CRP were determined at diagnosis and after 21 days of drug therapy. The primary efficacy measure was remission at 21 days, defined as a 75% or greater reduction in baseline CIBDAI score. Results: Differences between treatments in the rate of remission (both exceeding 80%) or the magnitude of its change over time were not observed. CRP concentrations in prednisone‐treated dogs were increased because of many dogs having active disease. Both treatments reduced CRP in comparison with pretreatment concentrations. An interaction between CIBDAI and CRP was identified in 42 of 54 dogs (78%), whereas 8 of 54 dogs (15%) showed disagreement between these indices. Conclusions and Clinical Importance: Prednisone is as effective as combined treatment with prednisone and metronidazole for induction therapy of canine IBD. CRP may be normal or increased in dogs with IBD and may be useful in assessing the response of individual dogs to treatment along with changes in the CIBDAI.