Cystitis laboratory findings
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Steven C. Campbell, M.D., Ph.D., Usama Talib, BSc, MD [2]
Overview
Presence of signs and symptoms of cystitis like dysuria, nocturia, frequency and urgency increase the probability of confirmation of cystitis as the diagnosis. Laboratory tests used in the diagnosis and confirmation of cystitis include urinalysis and urine culture. Laboratory findings consistent with the diagnosis of cystitis include pyuria and either white blood cells (WBCs) or red blood cells (RBCs) on urinalysis and a positive urine culture.
Laboratory Findings
- A urine sample is required to do urinalysis and urine culture to look for the causative organisms. Careful collection is required to minimise the contamination of the sample to decrease the false positive results.[1]
- Collection of urine from toilet trained children and adults by clean catch method is easy. Sample collection in children who are not toilet trained can be difficult and is achieved by either of these methods:[2][3][4]
- Suprapubic aspiration (up to 80% success rate when done with ultrasonography)
- Urethral catheterization
- Clean catch collection from urine bag
Of all these methods suprapubic aspiration has the least contamination rate that is around 1%, while that for transurethral catheterization has 6-12% and clean catch urine collected in a bag can have the highest contamination rate of 16-63%.[2][5][6] With any technique the rate of contamination can be decreased by discarding the initial stream of urine and collecting and using the middle stream of urine so that the bacteria already present on the skin or the catheter do not affect the results.[7][8]
Urine Sample Collection
Many aspects have to be taken care of while collecting a urine sample. The technique for urine sample collection is as follows:[2][9]
- The perineal area must be cleansed with an antiseptic or soap in young male or female children.
- Retraction of foreskin may be required if not circumcised.
- The patient must urinate in a toilet.
- The initial urine stream must not be collected.
- The midstream of urine is collected in a wide mouth bottle or container.
- For infants less than 6 months:[2][10]
- For infants and children more than 6 months old, a urine bag can be applied and removed after urine collection.
The sample collected must be sent to the lab as soon as possible since the warm temperature of the urine facilitates growth of pathogen and thus can lead to a falsely high count. An early report is helpful with initiating specific treatment. Storage at 4 degrees may be required if the sample can not be examined immediately.[11]
Urinalysis
Presence of nitrites or leukocyte esterase on dipstick or presence of WBCs of bacteria on microscopic examination suggests the presence of a urinary tract infection.[12][13][14]
- A urinalysis commonly reveals white blood cells (WBCs) or red blood cells (RBCs).
- Pyuria: > 5-10 WBC/hpf or 27 WBC/microliter
- Dipstick:
- Nitrate reductase test is used to differentiate between bacteria based on their ability or inability to reduce nitrate (NO3) to nitrite (NO2) using anaerobic respiration.
- Leukocyte esterase is a urine test for the presence of white blood cells and other abnormalities associated with infection.
Urine Culture
- Urine culture is done to identify the particular pathogen, so that the specific treatment can be given.[15]
Bacterial Culture
- A urine culture (clean catch) or catheterized urine specimen may be performed to determine the type of bacteria in the urine and the appropriate antibiotic for treatment.
- Most patients with urinary tract infection will have > 100,000 colonies of organism (CFU/mL).
Viral Culture
- The viruses involved in causing cystitis include HIV, adenovirus, cytomegalovirus and polyoma viruses. Viral cultures are only done in immunocompromised individuals or in those patients in whom the urinalysis and bacterial cultures are negative despite symptoms.[16]
Fungal Culture
- Candida is the most common fungus associated with fungal cystitis. Fungal cystitis is a rare when compared with bacteria cystitis. It can cause cystitis in immunocompromised patients only and presence of fungus in the urine is sometimes evaluated in hospitalised patients.[17]
References
- ↑ Shaikh N, Morone NE, Lopez J, Chianese J, Sangvai S, D'Amico F; et al. (2007). "Does this child have a urinary tract infection?". JAMA. 298 (24): 2895–904. doi:10.1001/jama.298.24.2895. PMID 18159059.
- ↑ 2.0 2.1 2.2 2.3 Labrosse M, Levy A, Autmizguine J, Gravel J (2016). "Evaluation of a New Strategy for Clean-Catch Urine in Infants". Pediatrics. 138 (3). doi:10.1542/peds.2016-0573. PMID 27542848.
- ↑ Pollack CV, Pollack ES, Andrew ME (1994). "Suprapubic bladder aspiration versus urethral catheterization in ill infants: success, efficiency and complication rates". Ann Emerg Med. 23 (2): 225–30. PMID 8304603.
- ↑ Gochman RF, Karasic RB, Heller MB (1991). "Use of portable ultrasound to assist urine collection by suprapubic aspiration". Ann Emerg Med. 20 (6): 631–5. PMID 1903907.
- ↑ Tosif S, Baker A, Oakley E, Donath S, Babl FE (2012). "Contamination rates of different urine collection methods for the diagnosis of urinary tract infections in young children: an observational cohort study". J Paediatr Child Health. 48 (8): 659–64. doi:10.1111/j.1440-1754.2012.02449.x. PMID 22537082.
- ↑ Al-Orifi F, McGillivray D, Tange S, Kramer MS (2000). "Urine culture from bag specimens in young children: are the risks too high?". J Pediatr. 137 (2): 221–6. doi:10.1067/mpd.2000.107466. PMID 10931415.
- ↑ Subcommittee on Urinary Tract Infection, Steering Committee on Quality Improvement and Management. Roberts KB (2011). "Urinary tract infection: clinical practice guideline for the diagnosis and management of the initial UTI in febrile infants and children 2 to 24 months". Pediatrics. 128 (3): 595–610. doi:10.1542/peds.2011-1330. PMID 21873693.
- ↑ Dayan PS, Chamberlain JM, Boenning D, Adirim T, Schor JA, Klein BL (2000). "A comparison of the initial to the later stream urine in children catheterized to evaluate for a urinary tract infection". Pediatr Emerg Care. 16 (2): 88–90. PMID 10784208.
- ↑ Vaillancourt S, McGillivray D, Zhang X, Kramer MS (2007). "To clean or not to clean: effect on contamination rates in midstream urine collections in toilet-trained children". Pediatrics. 119 (6): e1288–93. doi:10.1542/peds.2006-2392. PMID 17502345. Review in: Evid Based Med. 2007 Dec;12(6):178 Review in: Evid Based Nurs. 2008 Jan;11(1):25
- ↑ Herreros Fernández ML, González Merino N, Tagarro García A, Pérez Seoane B, de la Serna Martínez M, Contreras Abad MT; et al. (2013). "A new technique for fast and safe collection of urine in newborns". Arch Dis Child. 98 (1): 27–9. doi:10.1136/archdischild-2012-301872. PMID 23172785.
- ↑ Graham JC, Galloway A (2001). "ACP Best Practice No 167: the laboratory diagnosis of urinary tract infection". J Clin Pathol. 54 (12): 911–9. PMC 1731340. PMID 11729209.
- ↑ Huicho L, Campos-Sanchez M, Alamo C (2002). "Metaanalysis of urine screening tests for determining the risk of urinary tract infection in children". Pediatr Infect Dis J. 21 (1): 1–11, 88. PMID 11791090.
- ↑ Gorelick MH, Shaw KN (1999). "Screening tests for urinary tract infection in children: A meta-analysis". Pediatrics. 104 (5): e54. PMID 10545580.
- ↑ Hoberman A, Wald ER, Penchansky L, Reynolds EA, Young S (1993). "Enhanced urinalysis as a screening test for urinary tract infection". Pediatrics. 91 (6): 1196–9. PMID 8123075.
- ↑ KASS EH (1956). "Asymptomatic infections of the urinary tract". Trans Assoc Am Physicians. 69: 56–64. PMID 13380946.
- ↑ Allen CW, Alexander SI (2005). "Adenovirus associated haematuria". Arch Dis Child. 90 (3): 305–6. doi:10.1136/adc.2003.037952. PMC 1720282. PMID 15723924.
- ↑ Kauffman CA, Vazquez JA, Sobel JD, Gallis HA, McKinsey DS, Karchmer AW; et al. (2000). "Prospective multicenter surveillance study of funguria in hospitalized patients. The National Institute for Allergy and Infectious Diseases (NIAID) Mycoses Study Group". Clin Infect Dis. 30 (1): 14–8. doi:10.1086/313583. PMID 10619726.