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Urinalysis

  • Resource for Test Anaylsis

  • Glucose

    • False Positive False Negative
      Ketones Large amounts of Vitamin C
      Levodopa Elevated Specific Gravity
      Uric Acid

  • Blood

    • Detects both iron-containing heme pigment in both hemoglobin and myoglobin
    • Positive
      • Familial Causes
      • Glomerulonephritis
      • Malignant Hypertension
      • Nephrolithiasis
      • BPH
      • Drugs (NSAIDs, Heparin, Warfarin, Cyclophosphamide)
      • Trauma
    • False Positive False Negative
      Alkaline (>7.0) or Dilution (<1.010) Large amounts of Vitamin C
      Menstrual Blood Acidic (<5.1)
      Strenuous Exercise Captopril
      Some E. Coli
      Semen

  • Bilirubin

    • False Positive False Negative
      Phenazopyridium Chlorpromazine
      Selenium

  • Ketones

    • Elevation
      • Uncontrolled diabetes mellitus (diabetic ketoacidosis), pregnancy, carbohydrate-free diets, starvation, febrile illness
    • False Positive False Negative
      Acidic urine Delay in processing
      Elevated specific gravity
      Mesna
      Phenolphthalein
      Some drug metabolites (e.g., levodopa, captopril)

  • Leukocyte Esterase

    • Positive
      • Corticosteroids, Cyclophosphamide, Nephrolithiasis
    • False Positive False Negative
      Contamination Elevated Specific Gravity
      Glycosuria
      Ketonuria
      Proteinuria
      Cephalexin
      Nitrofurantoin
      Tetracyclines
      Gentamicin
      Vitamin C

  • pH

    • Normal: 4.5 to 8 (usually 5.5 to 6.5)
    • High Values (alkaline)
      • Stale/old urine specimens (most common), hyperventilation, presence of urease-producing bacteria, renal tubular acidosis, vegetarian diet, vomiting

  • Nitrites

    • False Positive False Negative
      Phenazopyridine (Azo) Elevated Specific Gravity
      Prolonged air exposure Elevated Urobilinogen
      Prolonged air exposure pH <6.0
      Prolonged air exposure Large amounts of Vitamin C
    • Phenazopyridine (Azo)
      • Analgesic for urinary tract mucosa frequently used to treat the dysuria of cystitis (after infection or instrumentation)
      • May worsen stone formation
        • SE: False-positive for nitrites on UA

  • Specific Gravity

    • False Positive False Negative
      Dextrans Alkaline urine
      Contrast Dye
      Proteinuria

  • Protein

    • Positive
      • Transient
        • CHF, Dehydration, Exercise, Fever, Seizures
      • Persistent
        • Primary or Secondary Glomerular Causes
        • Drugs (NSAIDs, Penicillamine, Gold, ACEI)
        • HIV/Syphilis, Hepatitis
    • False Positive False Negative
      Alkaline urine Acidic urine
      Phenazopyridine Dilution

  • Urobilinogen

    • Elevation
      • Increased production, decreased hepatic clearance, increased hepatic resorption
        • Hemolysis, liver disease (cirrhosis, hepatitis), sickle cell disease, thalassemia
    • False Positive False Negative
      Elevated nitrite levels
      Phenazopyridine
      Porphobilinogen
      Sulfonamides
      Aminosalicylic Acid

  • WBCs

    • Positive
      • Chlamydia, TB, Cancer, GN, Urethritis, Ureaplasma

  • Casts

    • Hyaline
      • Pyelonephritis, CKD
      • May be Normal
    • Erythrocyte
      • Glomerulonephritis
      • Contact Sports (Normal)
    • Granular, Waxy
      • Advanced Renal Disease
    • Fatty
      • Nephrotic Syndrome, Renal Disease, Hypothyroidism

Proteinuria

  • Transient Proteinuria
    • Increased glomerular permeability coupled with decreased proximal tubular reabsorption of protein
    • Seen in fever and after exercise
    • No further evaluation
  • Orthostatic Proteinuria
    • Benign condition in late teens/early adults (2-5%) up to age 30
    • Generally <1 g/day, may be up to 3g/day
    • Diagnosis: Quantitative proteinuria estimated by spot urine protein-to-creatinine upon arising (little, if any, proteinuria) and at the end of the day before recumbency (significant proteinuria)
    • Treatment
      • None required
  • Persistent Proteinuria
    • Increased permeability of glomerular capillary wall
    • Diagnosis: Renal US + Referral to Nephrologist
    • Differential
      • Reflux nephropathy
      • APKD