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Risk factors for blood-contaminated cerebrospinal fluid collection in dogs
  1. Aran Nagendran1,
  2. Daniel Sanchez-Masian1,
  3. Erika Bersan2,
  4. Camilla Jayne Cooper2 and
  5. Rita Gonçalves2
  1. 1 Veterinary Science, University of Liverpool, Neston, UK
  2. 2 School of Veterinary Science, University of Liverpool, Wirral, UK
  1. Correspondence to Aran Nagendran; anagen{at}


Objective To determine the risk factors for blood contamination during cerebrospinal fluid (CSF) collection in dogs.

Study design and methods This is a prospective study of 170 CSF samples. Data collected included signalment of the patient, body condition score, site of CSF collection (cerebellomedullary cistern (CMC) or lumbar cistern (LC)), number of attempts, clinician expertise, final diagnosis, time of day, skull conformation and day of the week. Analysis of the CSF samples was then performed, and the presence of blood contamination (red blood cells >500/µl) was recorded. Logistic regression was used to quantify the association of potential risk factors of the procedure. Multivariate analysis was performed on the variables that were statistically significant.

Results Of the 170 CSF samples, 53 per cent were collected from the CMC (n=90) and 47 per cent from the LC (n=80). Blood contamination was seen in 20 per cent (n=34) of the samples, 8.9 per cent (n=8) in CMC and 32.5 per cent (n=26) in LC samples. Increased odds of obtaining a contaminated CSF sample were associated with lower level of clinician expertise (odds ratio: 2.5; 95 per cent confidence interval: 0.9–6.7; P=0.046) and with LC versus CMC collection site (odds ratio: 8.1; 95 per cent confidence interval: 2.1–12.9; P=0.001).

Clinical significance There is increased likelihood of blood contamination when collecting CSF from the LC compared with the CMC site. Increased clinician experience reduced the risk of CSF blood contamination, but none of the other variables examined significantly influenced this.

  • Cerebrospinal fluid (CSF)
  • blood contamination
  • risk factors
  • lumbar cistern

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  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Ethics approval Ethical approval for use of data was granted by the Ethics Committee of the University of Liverpool (VREC416).

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement Data are available in a public, open access repository. There are no data in this work. All data relevant to the study are included in the article. Data are available upon request. Data may be obtained from a third party and are not publicly available. No data are available.

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