Urinalysis

Latest Edit: Hector 2014-03-21 (EDT)

See Also	Lab Tests

This test is part of routine diagnostic and screening evaluations. Urinalysis (UA) can provide useful preliminary information about the kidneys and other metabolic processes. Therefore it is a crucial part of routine monitoring in patients with chronic renal disease and some metabolic diseases.,

Discussion

• Total UA consists of multiple routine tests on a urine specimen.
• Routinely, UA includes information regarding the colour, appearance, and odour: pH, and the presence of proteins, glucose, ketones, blood, and leukocyte esterase.
• Urine is also examined microscopically for RBCs, WBCs, casts, crystals, and bacteria.

Patient Preparation

Factors which can cause increased levels:

Appearamce and colour:

• Sperm remaining in the urethra or retrograde ejaculation can cause the urine to appear cloudy
• Urine that has been refrigerated for more than one hour can become cloudy
• Certain foods: eating carrots can cause dark yellow urine, beets may cause red urine, rhubarb may cause reddish or brownish urine

Odor:

• Some foods (e.g., asparagus)
• the ammonia-like smell when urine stands for a long time and begins to decompose

pH:

• Urine becomes alkaline on standing due to the action of urea-splitting bacteria which produce ammonia
• the urine pH of an uncovered specimen will become alkaline because carbon dioxide vaporizes from the urine
• Dietary factors: ingestion of large quantities of citrus fruits, dairy products, and vegetables produce alkaline urine while meats and cranberries produce acidic urine

Drugs:bicarbonate antacids, carbonic anhydrase inhibitors, and acetazolamide

Protein:

• Transient proteinuria associated with emotional stress, excessive exercise, and cold baths
• Radiopaque contast media administered within 3 days
• Urine contaminated with prostate or vaginal secretions
• Diets high in protein
• Highly concentrated urine
• Hemoglobin

Drugs: acetazolamide, aminoglycosides, amphotericin B, cephalosporins, colistin, griseofulvin, lithium, methicillin, nafcillin, nephrotoxic drugs (e.g. arsenicals, gold salts), oxacillin, penicillamine, penicillin G, phenazopyridine, polymyxin B, salicylates, sulfonamides, tolbutamide, and vancomycin

Specific Gravity:

• Recent use of radiographic dyes
• Cold

Drugs: dextran and sucrose

Leukocyte Esterase:

• specimens contaminated by vaginal secretions (e.g. heavy menstrual discharge, Trichomonas infection, parasites) that contain WBCs

Ketones:

• Special diets (carbohydrate-free, high-protein, high-fat)

Drugs: bromosulfophthalein, isoniazid, isopropanol, levodopa, paraldehyde, phenazopyridine, and phenolsulfonphthalein (phenol red)

Biliruben and Urobilinogen:

• pH can affect urobilinogen levels: alkaline urine indicates higher levels

Crystals:

• Radiographic contrast media may cause precipitation of urinary crystals

WBC:

• Vaginal discharge may contaminate the urine and factitiously cause WBCs in thr urine

RBCs:

• Strenuous physical exercise
• Traumatic urethral catheterization
• Overaggressive anticoagulant therapy or bleeding disorders

Factors which can cause decreased levels:

pH:

Drugs: ammonium chloride, mandelic acid, and chlorothiazide

Leukocyte Esterase:

• high levels of protein or ascorbic acid

Bilirubin and Urobilinogen:

• pH can affect urobilinogen levels: acidic urine may show lower levels

Drugs: Cholestatic drugs, antibiotics reduce intestinal flora which in turn reduces urobilinogen levels

Clinical Implications

High levels indicate:

• pH:

• Alkalemia
• Urinary tract infections
• Gastric suction
• Vomiting
• Renal tubular acidosis

• Protein:

• Nephrotic syndrome
• Glomerularnephritis
• Malignant hypertension
• Diabetic glomerulosclerosis
• Polycystic disease
• Lupus erythematous
• Goodpasture syndrome
• Heavy-metal poisoning
• Bacterial pyelonephritis
• Nephrotoxic drug therapy
• Trauma
• Macroglubulinemia
• Multiple myelomas
• Preeclampsia
• Congestive heart failure
• Orthostatic proteinuria
• Severe muscle exertion
• Renal vein thrombosis
• Bladder tumor
• Urethritis or prostatitis
• Amyloidosis

• Specific Gravity:

• Dehydration
• Pituitary tumor or trauma
• Decreased renal blood flow ( as in heart failure, renal artery stenosis, or hypotension)
• Glycosuria and proteinuria
• Water restriction
• Fever
• Excessive sweating
• Vomiting
• Diarrhea

• Urobilinogen:

• Hemolytic anemia
• Pernicious anemia
• Hemolysis because of drugs
• Hematoma
• Excessive ecchymosis

• RBCs:

• Primary renal diseases (e.g. glomerulonephritis, interstitial nephritis, acute tubular necrosis, pyelonephritis)
• Renal tumor
• Renal trauma
• Renal stones
• Cystitis
• Prostatitis
• Tumors of the uterus and bladder
• Traumatic bladder catheterization
• Bladder trauma

• RBC casts:

• Glomerulonephritis
• Subacute bacterial endocarditis
• Renal infarct
• Goodpasture syndrome
• Vasculitis
• Sickling
• Malignant hypertention
• Systemic lupus erythmatosus

• WBCs:

• Bacterial infection in the urinary tract

• WBC Casts:

• Acute pyelonephritis
• Glomerulonephritis
• Lupus nephritis

Low levels indicate:

• pH:

• Acidemia
• Diabetes mellitus
• Starvation
• Respiratory acidosis
• Chronic obstructive pulmonary disease (COPD)

• Specific Gravity:

• Overhydration
• Diabetes insipidus
• Renal failure
• Diuresis

• Urobilinogen:

• Biliary obstruction
• Cholestasis

Presence of following indicate:

• Appearance and colour:

• Infection
• Gross hematuria
• Drug therapy
• Overhydration
• Diabetes insipidus
• Diuretic therapy
• Glycosuria
• Fever
• Excessive sweating
• Dehydration
• Jaundice
• Hemoglobinuria
• Myoglobinuria
• Porphyria

• Odour:

• Ketonuria
• Urinary tract infection
• Enterovesical fistula
• Maple sugar urine
• Phenylketonuria

• Leukocyte Esterase:

• Possible UTI

• Nitrites:

• Possible UTI

• Ketones:

• Poorly controlled diabetes mellitus
• Starvation
• Alcoholism
• Weight-reduction diets
• Prolonged vomiting
• Anorexia
• Fasting
• High-protein diets
• Glycogen storage diseases
• Febrile illness in infants and children
• Hyperthyroidism
• Severe stress or illness
• Excessive aspirin ingestion
• Anesthesia

• Bilirubin:

• Gallstones
• Extrahepatic duct obstruction (e.g. tumor, inflammation, gallstone, scarring, or surgical trauma)
• Extensive liver metastasis
• Dubin-Johnson syndrome
• Rotor syndrome

• Crystals:

• Renal stone formation
• Urinary tract infection

• Granular casts and waxy casts:

• Acute tubular necrosis
• Urinary tract infections
• Glomerulonephritis
• Pyelonephritis
• Nephrosclerosis
• Chronic lead poisoning
• Exercise
• Stress
• Renal transplant rejection

• Fatty Casts:

• Nephrotic syndrome
• Diabetic nephropathy
• Glomerulonephritis associate with streptococcal infection
• Chronic renal disease
• Mercury poisoning
• Fat metabolism

• Epithelial Casts:

• Glomerulonephritis
• Eclampsia
• Heavy-metal poisoning

• Epithelial Cells:

• Acute renal allograft rejection
• Acute tubular necrosis
• Acute glomerulonephritis because of streptococcal infection

• Hyaline Casts:

• Orthostatic proteinuria
• Fever
• Strenuous exercise
• Stress
• Glomerulonephritis
• Pyelonephritis
• Congestive heart failure
• Chronic renal failure

Associated Tests

• Glucose Urine Test, urine culture and sensitivity