Synonym

• Urine microscopic
• Microscopic urine examination
• Bacteria (Urine)
• Cells (Urine)
• WBC's (Urine)
• RBC's (Urine)

Tubes

• 10-20 mL urine in a disposable sterile plastic container or plain tube
• Midstream random urine sample to be collected

Additional information

• Use a freshly voided specimen
• Send specimen to lab immediately
• If delay of >1hr is expected, refrigerate the specimen
• Attention should be given to avoid having skin epithelium, secretions, hair, lint, etc from contaminating the sample
• Avoid preservatives or any other contamination
• Instructions for clean catch midstream urine collection:
• For male
• Wash hands thoroughly
• Cleanse the meatus
• Void a small amount into the toilet
• Then, void directly into the specimen container
• For female
• Wash hands thoroughly
• Cleanse the labia from front to back
• While keeping the labia separated, void a small amount into the toilet
• Without interrupting the urine stream, void directly into the specimen container

Info

• This test involves examination of the urinary sediment under a microscope (this is typically from a centrifuged specimen of urine)
• The urinary sediment consists of cellular elements, casts, crystals, and microorganisms
• Here, we describe the examination of the microorganisms and cells. The examination of urinary casts and crystals is described in a separate section.
• Cellular elements are composed of:
• Red blood cells
• White blood cells (leukocytes)
• Originate from anywhere in the genitourinary tract, and are capable of amoeboid migration through the tissues to sites of infection or inflammation
• Urinary epithelial cells
• Renal tubular epithelial cells – Occasional renal epithelial cells are common. Presence of bubble cells (containing large nonlipid vacuoles) and oval fat bodies (highly refractive and containing lipids) are associated with renal disease
• Bladder (transitional) epithelial cells line the urinary tract from the renal pelvis to the proximal two thirds of the urethra
• Squamous epithelial cells are urethral and vaginal in origin
• Microorganisms
• Organisms may be in chains or clusters and some are motile
• Bacteria, fungi including yeast, and protozoans including Trichomonas may be seen

Clinical

• The clinical utility of urine cellular elements and bacteria in routine urinalysis include:
• As a basic screening test performed as a part of
• Routine physical examination
• Pregnancy workup
• On admission to a healthcare facility
• Before surgery
• To evaluate kidney function
• To evaluate for urinary tract infection
• To evaluate for hematuria
• To evaluate for dysuria
• Evaluation and diagnosis of renal lesion or disease and infections of the lower urinary tract
• Evaluation of unexplained acute or chronic renal failure
• Evaluation of suspected urinary tract malignancy in high risk population
• Smokers
• Those exposed to aniline dye
• Previously treated for bladder cancer
• As an aid in the evaluation of acute glomerulonephritis
• As an aid in the diagnosis of acute interstitial nephritis (requires staining for eosinophils)
• Evaluation of hematuria seen on urine dipsticks test
• Examination of RBC's, leukocytes, and bacteria test results may be reported as few, moderate, large or TNTC (to numerous to count), or may be reported as 1+, 2+, 3+, or 4+
• Examination of RBC's and WBC's are most typically reported as cells per hpf (high powered microscopic field)
• Urinary sediment composed of increased leukocytes with bacteria is indicative of urinary tract infection (RBC's and epithelial cells may also be present)

Cellular elements

• RBC's (hematuria) indicate bleeding within genitourinary tract
• WBC clumps are suggestive of a renal origin
• Sterile pyuria is common in females with symptoms of UTI but with negative culture; this may indicate urethritis or can be non-specific
• Vaginal discharge can contaminate a specimen with WBCs

Microorganisms

• Bacteria, yeast cells, and parasites in urine sediment reflect genitourinary tract infection or contamination from the external genitalia, urethra or prostate
• Clue cells (cell wall of some bacteria causes adhesion to epithelial cells) are present in nonspecific vaginitis caused by
• Gardnerella vaginitis
• Bacteroides sp.
• Mobiluncus sp.
• Mycoplasma hominis
• Yeast cells may be mistaken for RBCs. They are identifiable by their ovoid shape, lack of color, variable size, and signs of budding
• Most common parasite in urinary sediment is Trichomonas vaginalis (which is felt to be a sexually transmitted disease)

Additional information

• WBC's in the urine do not always mean bacteriuria
• In men,low bacterial counts with uropathogens (E. coli, Staphylococcussaprophyticus, and enteric Gram-negative bacteria) may be clinically important,as contamination is rare in males
• Asymptomatic bacteriuria is extremely rare in early childhood, but is common in the elderly
• Asymptomatic bacteriuria and leukocyturia is common in patients undergoing hemodialysis
• There is a debate on whether or not to treat asymptomatic bacteriuria, in the elderly, with antibiotics (typically only indicated if symptomatic)
• Asymptomatic bacteriuria should typically be treated in pregnancy, as ureteral dilatation is common and ascending infection can easily occur
• The US Preventive Services Task Force (USPSTF) recommends that all pregnant women be screened, at 12 to 16 weeks of gestation, for asymptomatic bacteriuria. However, it recommends against the routine screening of men and nonpregnant women for asymptomatic bacteriuria. There is not much evidence that such screening improves clinical outcomes.

Related laboratory tests include:

• Bladder cancer markers
• Blood and urine creatinine
• Blood and urine electrolytes
• Blood and urine protein
• Blood and urine urea nitrogen
• Complete blood count
• Urine culture

Nl Result

Consult your laboratory for their normal ranges as these may vary somewhat from the ones listed below.

RBC's and WBC's are typically reported as the number of cells seen in one high powered microscopic field of view (cells/hpf).

Notes:

• Normally women may have slightly more WBCs
• Squamous epithelial cells are common in normal urine sample
• Usually there should be either none or rare (<3/hpf) renal, transitional or squamous cells in the urine

High Result

Cellular elements

Conditions associated with increased RBCs (5 RBCs/hpf) in the urine include:

• Glomerular causes
• Alport's syndrome (Hereditary nephritis)
• Fabry's disease
• Glomerulonephritis
• Focal segmental
• Mesangioproliferative
• Post infectious (Post-streptococcal)
• Primary or Secondary
• Rapidly progressive
• Goodpasture's disease
• Henoch-Schönlein purpura
• IgA nephropathy (Berger's disease)
• Nail-patella syndrome
• Thin basement-membrane disease
• Hemolytic-uremic syndrome
• Systemic lupus nephritis
• Thrombotic thrombocytopenic purpura
• Vasculitis
• Renal causes
• Arteriovenous malformation
• Hypercalciuria
• Hyperuricosuria
• Loin pain-hematuria syndrome
• Malignant hypertension
• Medullary sponge kidney
• Papillary necrosis
• Polycystic kidney disease
• Renal artery embolism
• Renal vein thrombosis
• Tubulointerstitial causes
• Urologic causes
• Benign prostatic hyperplasia
• Cancer of kidney, ureteral, bladder, prostate, or urethra
• Cystitis/pyelonephritis
• Nephrolithiasis
• Prostatitis
• Schistosoma hematobium infection
• Tuberculosis
• Drugs (given below)
• Trauma as in contact sports, running, catheterization
• Hemolytic anemias
• Sickle cell anemia
• Glucose-6-phosphate dehydrogenase deficiency
• Paroxysmal hemoglobinuria
• Thalassemia
• Fava bean sensitivity
• Hemoglobinopathies
• Coagulation disorders
• Systemic causes
• Disseminated intravascular coagulation (DIC)
• Endocarditis
• Heart failure
• Malaria
• Malignant hypertension
• Tuberculosis
• Vasculitis
• Scurvy
• Gout
• Infectitious mononucleosis
• Leukemia
• Thrombocytopenia
• Other conditions
• Abdominal aortic aneurysm disection
• Benign familial or recurrent hematuria
• Bleeding disorders such as hemophilia
• Bleeding resulting from operative procedures on the prostate
• Certain chemical agents and alkaloids such as poisonous mushrooms, snake venom
• Dehydration
• Diverticulitis
• Extensive burns
• Febrile illnesses
• Heavy smoking
• Strenuous exercise ("march hemoglobinuria")
• Transfusion reactions
• Salpingitis
• Drugs and substances
• Abciximab
• Aldesleukin
• Alprostadil
• Alteplase
• Amphotericin
• Ardeparin
• Aspirin
• Auranofin
• Aurothioglucose
• Bacitracin
• Basiliximab
• Bcg vaccine
• Bicalutamide
• Candesartan
• Carvedilol
• Cefuroxime
• Chlorothiazide
• Cidofovir
• Clofibrate
• Clopidogrel
• Cyclophosphamide
• Danazol
• Diethylstilbestrol
• Donepezil
• Doxorubicin
• Ethosuximide
• Etretinate
• Fenoprofen
• Gabapentin
• Ganciclovir
• Gemcitabine
• Gold
• Goserelin
• Ibuprofen
• Indinavir
• Indomethacin
• Isotretinoin
• Itraconazole
• Ketoprofen
• Ketorolac
• Lansoprazole
• Leuprolide
• Lomefloxacin
• Mefenamic acid
• Mesalamine
• Metyrosine
• Mirtazapine
• Misoprostol
• Mycophenolate
• Naproxen
• Nisoldipine
• NSAIDs
• Octreotide
• Ofloxacin
• Olsalazine
• Omeprazole
• Oxaprozin
• Oxycodone
• Paroxetine
• Pegaspargase
• Penicillamine
• Piroxicam
• Probenecid
• Pyrimethamine
• Rifampin
• Risperidone
• Sargramostim
• Somatotropin
• Sulfasalazine
• Sulfisoxazole
• Sulindac
• Thiabendazole
• Ticlopidine
• Tolazoline
• Tolcapone
• Tolmetin
• Trastuzumab
• Urokinase
• Venlafaxine
• Warfarin

Conditions associated with elevated leukocytes (pyuria) include:

• Uro-genital infections
• Cystitis
• Epididymitis
• Pelvic inflammatory disease (PID)
• Prostatitis
• Pyelonephritis
• Urethritis
• Appendicitis
• Bladder tumors
• Diverticulitis
• Febrile illnesses
• Glomerulonephritis
• Interstitial nephritis
• Intra-abdominal abscess
• Lupus erythematosus
• Noninfective inflammatory disease
• Pancreatitis
• Peritonitis
• Tuberculosis
• Kidney transplant rejection
• Strenuous exercise

Conditions associated with large number of lymphocytes and plasma cells in the urine:

• Acute renal allograft rejection

Conditions associated with eosinophils in the urine include:

• Tubulointerstitial disease
• Hypersensitivity to penicillin

Conditions associated with presence of numerous epithelial cells in the urine include:

• Renal tubular epithelial cells
• Kidney transplant rejection
• Renal tubular degeneration
• Acute tubular necrosis
• Acute glomerulonephritis
• Malignant nephrosclerosis
• Pyelonephritis
• Urolithiasis
• Viral infections - CMV
• Poisoning from heavy metals or other toxins
• Eclampsia
• Drugs and substances
• Chemotherapeutic drugs
• Ethylene glycol
• Lead
• Salicylate overdose
• Transitional cells are seen with infection, trauma, or malignancy of the:
• Bladder
• Renal pelvis
• Ureter
• Urethra (proximal portion)
• Abnormal squamous cells with enlarged nuclei indicate the need for cytological studies to rule out malignancy

Conditions where spermatozoa may be seen in the urine include:

• Male urine related to recent or retrograde ejaculation

Microorganisms

Presence of bacteria, fungi, and parasites in the urine is indicative of:

• Cystitis
• Epididymitis
• Pelvic inflammatory disease (PID)
• Prostatitis
• Pyelonephritis
• Vaginitis
• Urethritis

Factors causing false positive results include:

• Improper collection or transport
• Alkaline urine hemolyzes RBCs and dissolves casts
• Yeast or oil droplets may be mistaken for RBCs
• Vaginal discharge can contaminate a specimen with WBCs

References

• Kouri T et al. Preservation of urine for flow cytometric and visual microscopic testing. Clin Chem. 2002 Jun;48(6 Pt 1):900-5.
• Laboratory Corporation of America®. Urinalysis, Complete With Microscopic Examination. [Homepage on the internet]©2003. Last updated on September 15, 2003. Last accessed on November 24, 2006. Available at URL: http://www.labcorp.com/datasets/labcorp/html/chapter/mono/ur002700.htm
• LabTestsOnline®. Urinalysis. [Homepage on the Internet] ©2001-2006. Last reviewed on May 9, 2005. Last accessed on November 24, 2006. Available at URL: http://www.labtestsonline.org/understanding/analytes/urinalysis/ui_exams-3.html
• Lamchiaagdhase P et al. Urine sediment examination: a comparison between the manual method and the iQ200 automated urine microscopy analyzer. Clin Chim Acta. 2005 Aug;358(1-2):167-74.
• Leman P. Validity of urinalysis and microscopy for detecting urinary tract infection in the emergency department. Eur J Emerg Med. 2002 Jun;9(2):141-7.
• Simerville JA et al. Urinalysis: A Comprehensive Review. Am Fam Physician. 2005 Mar 15;71(6):1153-62.
• UTMB Laboratory Survival Guide®. URINALYSIS (Chemistry and Microscopic). [Homepage on the Internet]©2006. Last reviewed in February 2006. Last accessed on November 23, 2006. Available at URL: http://www.utmb.edu/lsg/LabSurvivalGuide/chem/URINALYSIS.html
• van Rossum AM et al. Persistent sterile leukocyturia is associated with impaired renal function in human immunodeficiency virus type 1-infected children treated with indinavir. Pediatrics. 2002 Aug;110(2 Pt 1):e19.