Urine dipstick

Note: Urinalysis (UA) can be done at bedside (dipstick) or in laboratory, this page will focus on bedside (dipstick)

Specific Gravity (Normal 1.003-1.030)

  • Related to serum/urine osmolality (kidney's ability to concentrate or dilute urine)
  • <1.003
    • Excessive hydration
    • Nephrogenic diabetes insipidus
    • gGomerulonephritis
    • Pyelonephritis
    • Acute tubular necrosis
  • Fixed levels 1.010
    • End stage renal disease
    • Chronic glomerulonephritis
  • >1.030
    • Dehydration
    • SIADH
    • Adrenal insufficiency
    • Other: Liver failure, nephrotic syndrome, and prerenal renal disease
  • False decrease glycosuria, proteinuria, IV contrast, urine contamination

pH (Normal 5.5-6.5)

  • High pH
    • Vegetarians
    • UTI (urea-splitting bacteria)
    • Alkalemia (metabolic vs. respiratory)
    • Type 1 renal tubular acidosis
    • Drugs (Salicylate, antibiotics, acetazolomide)
  • Low pH
    • High protein-fat diet
    • Acidemia (normal renal response)
    • Diabetes, DKA
    • Starvation
    • Diarrhea
    • Metabolic disorder (Phenylketonuria)

Protein (Negative-Trace)

  • Dipstick positive at 5-10mg/dL (normal to have <150mg/dL protein per day)
  • High protein
    • Renal
      • Renal tubular secretion, increased filtration, pyelonephritis, glomerulonephritis, znephrotic and nephritic syndrome
    • Drugs
      • Aminoglycosides, gold, amphotericin, NSAID, sulphonamides, penicillins
    • CHF
    • Preeclampsia
    • Other: Pregnancy, physiologic stress, exercise, fever, cold exposure
  • Mostly detects albumin, so may NOT detect
    • Bence Jones globulin (multiple myeloma, lymphoma, and macroglobulinemia)
    • Microalbuminuria (30-300 mg/day)
  • Can be affected by dilution (check urine concentration)

Leukocyte Esterase (Negative)

  • Associated with pyuria >10WBC per hpf
  • Positive
    • Contamination
    • Trichomonas vaginalis
    • Drug/foods that colour urine red
  • False negative
    • Less than 30 seconds to 2 minutes of urine contact
    • Low bacteria count
    • Gycosuria, proteinuria, high specific gravity

Nitrite (Negative)

  • Requires 4h of incubation within bladder with >10,000 gram-negative bacteria (E. coli) per mL urine
  • False positive
    • Exposure to air (1/3 false positive after one week, 3/4 at two weeks)

Blood (Negative)

  • Peroxidase activity
    • Hematuria
      • Trauma, infection, inflammation, calculi, neoplasm, clotting disorder, burns, cold, eclampsia, sick cell crisis, transfusion reaction, exercise, and infarction
    • Hemaglobinuria (intravascular hemolysis)
    • Myoglobinuria (crush injury, electrocution, rhabdomyolysis)
    • Ascorbic acid or antiseptic povidone iodine (Betadine)
  • Diets high Vitamin C can result in false negative (affects peroxidase activity)

Glucose (Negative)

  • Usually detected in urine when serum levels >180mg/dL
    • Hyperglycemia diabetes, Cushing’s disease, liver disease, and several congenital/metabolic conditions
    • Renal disease (failure to resorb glucose in proximal tubule)
    • Drugs (cephalosporins, penicillins, nitrofurantoin, methyldopa, tetracycline, lithium, carbemazepine, phenothiazines, steroids and thiazides)

Ketones (Negative)

  • Low carbohydrate (high fat/protein) diets, starvation,
  • diabetes, alcoholism, hyperthyroidism, and eclampsia
  • Overdose
    • Insulin, isoniazid, and isopropyl alcohol
  • Underestimates ketonemia (nitroprusside less sensitive than beta-hydroxybutyric acid - the predominant ketone in DKA)

Bilirubin (Negative)

  • Raised conjugated bilirubin (water soluble)
    • Hepatocellular disease
    • Cirrhosis
    • Hepatitis
    • Biliary obstruction
    • Inherited

Urobilinogen (0.2-1.0 mg/dL)

  • Positive (Bilirubin turnover)
    • Hemolysis, Malaria
    • Liver disease
  • Decreased or absent
    • Bile duct obstruction
    • Specific antibiotics