Catheter Specimen of Urine

Specimens of urine are frequently collected from patients for microbiological and/or biochemical investigations and toxicology screening. Testing of a urine specimen is to identify the micro-organisms causing infection and their sensitivities to antimicrobial agents (Shepherd 2017).  If a patient has an indwelling urinary catheter in situ and a urine sample is required, then a catheter specimen of urine (CSU) is obtained.

There is a much higher risk of patients acquiring a urinary tract infection if they have an indwelling urinary catheter in situ and the risk of infection appears to increase with the duration of catheterisation (Loveday et al. 2014, National Institute for Health and Care Excellence (NICE) 2014). Catheter-associated urinary tract infections (CAUTIs) account for approximately 80% of all hospital-acquired infections (Parker et al. 2017). However, the presence of bacteria does not always specify infection because urine from all patients with urinary catheter will contain bacteria. It is vital, therefore, that CSUs are only taken when clinically indicated and that when obtaining the specimen strict infection prevention control procedures and aseptic principles are followed (Loveday et al. 2014, Royal College of Nursing (RCN) 2019).

A CSU is obtained from the sampling port on the urine drainage tubing by aspirating the urine using a syringe only. As sampling ports are closed systems, the risk of infection is reduced when obtaining a CSU. Moreover using a needle-free port reduces the risk of needlestick injuries.

A CSU cannot be taken from tubing that does not have a sampling port as the tubing is not designed to be punctured with a needle; it will not seal properly and will increase the risk of infection. Specimens of urine must not be collected via the drainage tap on the catheter bag as it will not be a clean specimen because urine tends to stagnate in the bag and colonisation of micro-organisms may have occurred.

PREPARATION AND SAFETY

• Explain the procedure, to gain the patient’s consent and cooperation.

• Maintain the patient’s dignity and privacy throughout the procedure.

• If there is no urine present in the catheter tubing, clamp it below the sampling port for 15–20 min to allow urine to collect. Use a non-toothed clamp to prevent damage to the tubing.

• Perform hand hygiene and put on a disposable apron and non-sterile gloves.

• Wear personal protective equipment where necessary.

PROCEDURE

1. Explain to the patient what you are going to do and expose the drainage tubing.
   Rationale – Consent from the patient is required and an explanation of the procedure is needed so that the patient agrees. The drainage tubing must be exposed as this is the site from which the specimen will be collected.

2. Open the alcohol-impregnated swab and clean the sampling port on the tubing. Allow the swabbed site to dry for 10–30 seconds.
    Rationale – A sterile procedure is required to minimise the risk of infection to the patient and contamination of the sample from organisms on the outside of the tubing.

3. Remove the syringe from its packaging using an aseptic non-touch technique.
   Rationale – To prevent contamination of the syringe tip, which would contaminate the specimen.

4. Insert the tip of the syringe into the needle-free sampling port at a 90˚ angle to the tubing and aspirate the required amount of urine; 10 mL is usually sufficient.
   Rationale – Do not use a needle to aspirate urine through a needle-free port. The needle-free port is a closed system and puncturing it will create an open site and increase the risk of infection. 

5. Withdraw the syringe from the sampling port and clean the port again using an alcohol-impregnated swab.
   Rationale – Minimises the risk of infection.

6. Transfer the specimen of urine collected in the syringe into the pre-labelled sterile specimen container and replace the lid securely. Label the container with the patient’s details as per local policy.  
   Rationale – A sterile procedure is required so that the sample is not contaminated. 

7. Dispose of syringe safely.
    Rationale – Correct disposal of syringes minimises the risk of cross-contamination.

8. Unclamp the drainage tubing (if applicable).
   Rationale – To allow drainage of urine to continue.

9. Remove gloves and apron and wash hands.
   Rationale – Immediate disposal of protective wear following a clinical procedure minimises the risk of cross-infection.

10. Sign the pathology form and affix the label with the patient’s details.
    Rationale – To ensure that the specimen is correctly identified. This should include patient details, reason for the specimen, and signature of the person collecting the specimen. Local policies and procedures must be followed.

11. Place the specimen container in the specimen bag, seal it, and insert the pathology request form into the pocket of the bag.
    Rationale – Compliance with local policies and procedures is essential to ensure specimens are correctly labelled and are safe for storage to the laboratory. The use of a specimen bag to transport the specimen will enable safe transfer and reduce the risk of contamination in the unlikely event that the specimen container is damaged and spillages occur.

12. Document the procedure.
    Rationale – Effective record keeping is essential in line with RCN standards (RCN 2017).

13. Make the patient comfortable.
    Rationale – Ensuring that the patient is comfortable is an integral aspect of promoting dignity. The patient may require help with moving and positioning.

ONGOING CARE, MONITORING, AND SUPPORT

• Ensure the patient is comfortable.

• Label the specimen with the patient’s surname, first name, date of birth, hospital number, ward, and date, time, and type of specimen (i.e., CSU).

• Place the specimen in a plastic specimen bag with the laboratory request form.

• Place the specimen in the refrigerator for dispatch to the laboratory as soon as possible. The specimen should be placed in a refrigerator because urine readily supports growth of bacteria. The multiplication of bacteria in specimens stored at room temperature can give misleading results (NICE 2014).

• Document the date and time of specimen collection in the patient’s records.

DOCUMENTATION AND REPORTING

• Document obtaining the specimen according to local policies and guidelines.

• Report any abnormalities or complications.

EQUIPMENT

• 2 alcohol-impregnated swabs.

• Non-toothed clamp to prevent damage to the tubing.

• A 20 mL syringe.

• Sterile universal specimen container.

• Non-sterile gloves and disposable apron.