In Volume 1, Issue 3 of the Care Home Nursing Journal (CNJ) Louise Morris, Care Home Assistant Practitioner Project Lead, Four Seasons Health Care discusses the literature around the effective use of urinalysis dipstick testing to diagnosis urinary tract infection and highlights when urinalysis should be used as well as best practice for obtaining an accurate result. In this blog we highlight Louise’s key messages and the supporting research:
Key messages when using urinalysis to diagnose urinary tract infection (UTI)
- Urinalysis dipstick testing should only be carried out when indicated by symptoms - not routinely
- False results can occur if guidelines are not strictly adhered to
- Sample collection methods do not affect the reliability of the test
- Specimens do not need to be sent for laboratory testing to confirm diagnosis of UTI
- A positive result for nitrites and leukocytes without the presence of symptoms often does not need treatment
Individual patient symptoms and history | Inappropriate diagnosis of UTI
UTI incidence has been shown to increase with age, and urinalysis is commonly used to detect UTI in elderly individuals in long-term care. Deville et al. (2004) demonstrated that the urine dipstick test appears to be useful to exclude the presence of infection if the results of both nitrites and leukocytes were negative. They found that the sensitivities of the combination of testing for both nitrites and leukocytes can vary between 68% and 88% in different patient groups. Concluding that although the combination of positive test results can be very sensitive, the usefulness of the dipstick test alone to rule-in infection is unreliable.
A later study by Bhavsar et al. (2015) found that without clinical information, screening of UTI by the presence of leukocytes and/or nitrites gave poor results. Similarly, Frazee, Enriquez, Ng and Alter (2014) agreed that abnormal urinalysis results are common in women without infection and Nazarko (2009) claims that half of all women with urinary tract symptoms have urethritis rather than a UTI.
Benton et al. (2008) specifically discusses asymptomatic bacteriuria within residents in long-term care and evidenced that with increasing level of care, there was a successive increase in asymptomatic bacteriuria prevalence and that treating it can potentially cause more harm than good in long-term care residents. This supports not routinely dip-testing urine and that abnormal urinalysis results without symptoms of UTI is very common. Benton et al. (2008) go on to recommend that if a resident appears ill but there are no symptoms clearly arising from the urinary tract, other sources should be sought for the change in clinical status.
These studies highlight that inappropriate diagnosis of UTI potentially exposes patients to hazards of antibiotics and contributes to antibiotics resistance. Therefore, routine testing of samples should be discouraged and urinalysis results must be looked at in context with patient symptoms and history.
The reliability of the urinalysis dipstick result is commonly thought to be dependent on the method of sample collection. A mid-stream sample of urine was considered to be the gold standard method of collecting a sample. However it is not always possible for older adults to provide a mid-stream urine sample due to incontinence, dexterity or capacity to understand the instructions given.
Although prior cleansing often is recommended, it has no proven benefit (Lifshitz and Kramer 2000, Simerville et al. 2005) and cleansing with antiseptic has been shown to lead to false negatives (PHE, 2017). Frazee et al. (2014) demonstrated that reliable results are not dependent on sample methods. Catheter specimens should always be taken from the sampling port (PHE, 2017).
Urine collection pads are another method that is used when it is impractical to pass urine into a container, however this should be a last resort as artificially elevated leukocyte counts may occur when pad collection is used (PHE, 2017). When using this method, effort should be made to test as soon as possible. A tip of a sterile syringe should be inserted into the pad to draw urine into the syringe and the urine transferred directly into a sterile sample bottle. If difficulty is experienced in withdrawing urine, the wet fibres may be inserted into the syringe barrel and the urine squeezed directly into the container with the sterile syringe plunger, taking care not to contaminate the specimen.
Registered Nurses can delegate this task to unregistered staff (e.g. Care Home Assistant Practitioners (CHAPs)) that have current evidence of training and competence. The nurse can delegate collecting the sample, preforming the urinalysis dipstick test, recording the result in the notes. However the Nurse would need to interpret the result and write any clinical instructions within the care plan.
Testing and analysis
Delays to testing urine and storage at room temperature allow organisms to multiply, which can give false positive nitrite results (PHE, 2017). If urine is stored in the fridge, it should be allowed to return to room temperature before testing (Wilson, 2005).
It is considered to be best practice is to use computerised urine analysers allow the user to view the result on a small screen and then print a copy for the records. This is more convenient and produces greater accuracy in results (Wilson, 2005). In the care home environment, computerised analysers are not readily available due to budgetary constraints. Manual visual analysis is used widely, meaning there is greater need for thorough training to avoid user error:
Best Practice guidelines for manual visual urinalysis:
- Check specimen has been labelled correctly if not testing immediately after collection
- Test specimen as soon as practicable after collection and no later than 2 hours
- Allow urine stored in the fridge to return to room temperature
- Wash hands and apply gloves and apron
- Note colour, clarity and odour of urine
- Check expiry date on urinalysis dipsticks container
- Check urinalysis dipsticks have been stored correctly (in line with manufacturers’ instructions) with lid securely fastened
- Remove one dipstick, taking care to only touch the plastic handle and not the reagent strip, replace the lid on the container immediately
- Fully immerse the dipstick so that all reagent test pads are covered and remove after approximately 2 seconds
- Tap the side of the container or on absorbent paper to remove the excess urine
- Hold dipstick horizontally to prevent contamination of adjacent reagent test pads
- Use a timer to measure exact time according to manufacturers’ instructions, noting that timing can vary between 20 seconds and 2 minutes between individual reagent test pads, depending on the brand
- Record the results, informing patient/resident, Registered Nurse and GP as appropriate
Interpreting the result
Results should always be looked at in conjunction with symptoms and clinical presentation. According to PHE (2017), the presence of blood, leukocytes and nitrites indicate probable UTI. Negative nitrite and positive leucocytes does not rule in or out UTI and other causes of symptoms are equally likely. The presence of blood and protein, without nitrites or leukocytes would not indicate UTI, but would need investigating further for other diagnosis.
Recording urinalysis results
Firstly record symptoms and reason for the test. This makes it clear why urinalysis dipstick testing was carried out. Colour, clarity and odour should also be recorded along with the result of the urinalysis dipstick (Yates, 2016 and Bulloch et al. 2000). Negative results should also be recorded as this shows that UTI has been ruled out as a cause of symptom. Also record who was informed of the result and the resulting plan of care.
The decision of whether to send a specimen for culture and sensitivity testing varies considerably among practitioners. The only conclusive diagnostic test for UTI is a full culture and sensitivity test performed by the laboratory, which is time consuming and a drain on NHS resources (McNulty et al. 2008). It is recommended that prescribing on the results of urinalysis and clinical symptoms should be considered as best practice, however GPs have local guidelines to follow so ensure you seek their advice.
Benton TJ, Young RB, Leeper SC (2008) “Asymptomatic bacteriuria in the nursing home.” ALTC. 14(7):17-22. Available from: http://www.managedhealthcareconnect.com/article/5963
Bhavsar, T, Potula, R, Jin, M, Truant, A (2015) “Predictability of urinalysis parameters in the diagnosis of urinary tract infection: a case study” Medical Laboratory Observer 47(1):8, 10
Bulloch B, Bausher JC, Pomerantz WJ, Connors JM, Mahabee-Gittens M, Dowd MD. (2000) “Can urine clarity exclude the diagnosis of urinary tract infection?” Pediatrics. 106(5):60. Available from: https://www.ncbi.nlm.nih.gov/pubmed/11061797.
Deville W, Yzermans JC, Duijn NP, Bezemer PD et al (2004) “The urine dipstick test useful to rule out infections. A meta-analysis of the accuracy”. BMC Urology 4:1–14
Frazee, B.W; Enriquez, K; Ng, V; Alter, H (2014) “Abnormal urinalysis results are common, regardless of specimen collection technique, in women without urinary tract infections” The Journal of Emergency Medicine Vol 48 Issue 6
Lifshitz E, Kramer L. (2000) “Outpatient urine culture: does collection technique matter?”Archives Internal Medicine. 160(16): 2537-2540. Available from: https://www.ncbi.nlm.nih.gov/pubmed/10979067
McNulty C, Bowen J, Howell-Jones R, Walker M, Freeman E (2008) “Exploring reasons for variation in urinary catheterisation prevalence in care homes: a qualitative study” Age and Ageing 37(6): 706–10
Nazarko, L. (2009) “Combating antibiotic resistance in urinary tract infection” Nurse Prescribing 7(10)450-5 Public Health England (PHE). (2017). “Diagnosis of Urinary Tract Infection. Quick Reference Guide for primary care for consultation and local adaptation”. Available from: https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/619772/Urinary_tract_infection_UTI_guidance.pdf
Public Health England (PHE). (2017). “Management of infection guidance for primary care for consultation and local adaptation”. Available from: https://www.gov.uk/government/ publications/managing-common-infections-guidance-for-primary-care
Simerville, J, Mazted, M and Pahira, J. (2005)”A midstream cleancatch technique usually is adequate in men and women”. American Family Physician 71(6):1153-1162
Wilson, L (2005). “Urinalysis” Nursing Standard 19(35) 51-54
Yates, A. (2016) “Urinalysis, How to Interpret the Results” Nursing Times Online 112(2)