Urinalysis

Observation

Urine Color

  • Black Urine
    • Hemoglobinuria
    • Myoglobinuria
    • Ochronosis: alkaptonuria (“black urine disease”) due to excretion of homogentisic acid (black color may only appear after urine stands for a period of time, allowing oxidation of homogentisic acid)
  • Blue Urine
  • Green Urine
    • Amitriptyline (Elavil) (see Amitriptyline, [[Amitriptyline]])
    • FD&C Blue Dye in Tube Feedings
    • Methylene Blue (see Methylene Blue, [[Methylene Blue]])
    • Metoclopramide (Reglan) (see Metoclopramide, [[Metoclopramide]])
    • Promethazine (Phenergan) + Cimetidine (see Promethazine, [[Promethazine]] and Cimetidine, [[Cimetidine]])
    • Propofol (see Propofol, [[Propofol]]): propofol is metabolized and excreted as phenolic metabolites, which cause the green discoloration
      • Green urine is a benign side effect of propofol infusion
      • It has been reported with both short-term and long-term use of propofol
  • Pink Urine
    • Propofol (see Propofol, [[Propofol]]): presumably due to presence of uric acid crystals
  • Red Urine
    • Beet Ingestion
    • Hematuria (see Hematuria, [[Hematuria]])
    • Hemoglobinuria (Urine Hemoglobin)/Hemosiderinuria (Urine Hemosiderin) (see Hemoglobinuria, [[Hemoglobinuria]] and Hemosiderinuria, [[Hemosiderinuria]])
      • Hemolytic Anemia (see Hemolytic Anemia, [[Hemolytic Anemia]])
      • Hemoglobin Binds to Haptoglobin: imparts a red color to plasma
    • Myoglobinuria (see Myoglobinuria, [[Myoglobinuria]])
      • Rhabdomyolysis (see Rhabdomyolysis, [[Rhabdomyolysis]])
      • Myoglobin is a Low Molecular Weight (17 kDa) Heme Pigment, Which Does not Bind to Haptoglobin: therefore, it is not present to any significant extent in the plasma
    • Porphyrinuria
  • Red-Brown Urine (May Be “Coca Cola”-Colored)
    • Beet Ingestion
    • Hemoglobinuria (Urine Hemoglobin)/Hemosiderinuria (Urine Hemosiderin) (see Hemoglobinuria, [[Hemoglobinuria]] and Hemosiderinuria, [[Hemosiderinuria]])
      • Hemolytic Anemia (see Hemolytic Anemia, [[Hemolytic Anemia]])
        • Hemoglobin Binds to Haptoglobin: imparts a red color to plasma
    • Myoglobinuria (see Myoglobinuria, [[Myoglobinuria]])
      • Rhabdomyolysis (see Rhabdomyolysis, [[Rhabdomyolysis]])
        • Myoglobin is a Low Molecular Weight (17kDa) Heme Pigment, Which Does not Bind to Haptoglobin: therefore, it is not present to any significant extent in the plasma
  • Orange Urine
    • Phenazopyridine (Pyridium)* (see Phenazopyridine, [[Phenazopyridine]]): with associated orange secretions
    • Rifampin (see Rifampin, [[Rifampin]]): with associated orange secretions
  • Purple Urine
    • Bacteriuria in Patient with Foley Catheter
  • White Urine
    • Chyluria
    • Phosphate Crystals
    • Propofol (see Propofol, [[Propofol]]):
    • Pyuria

Urine Dipstick

Urine pH

  • xxx

Urine Specific Gravity

  • xxx

Urine Glucose

  • Etiology of Positive Urine Glucose

Urine Ketones

  • Technique
    • Nitroprusside Reaction (only detects acetoacetate and, to a far lesser extent, acetone): may be negative or only weakly positive
      • Acetest (Using Nitroprusside Tablets)
      • Ketostix (Using Nitroprusside Reagent Sticks)
      • False-Positive Nitroprusside Test: may be due to drugs with sulfhydryl groups (captopril, penicillamine, mesna), which react with nitroprusside
  • Etiology of Positive Urine Ketones

Urine Occult Blood

  • Technique: utilizes the characteristic of heme to act as a pseudoperoxidase -> when heme-containing urine is exposed to a peroxide and chromogen, a color change occurs
    • Sensitivity: urine dipstick for occult is highly sensitive and can detect 1-2 red blood cells per high-powered field
    • Presence of Ascorbic Acid (Vitamin C) May Result in a False-Negative Test (see Vitamin C, [[Vitamin C]]): vitamin C interferes with the peroxidase reaction
      • Some dipsticks are able to oxidize vitamin C to mitigate this issue
  • Etiology of Positive Urine Occult Blood Test
    • Hematuria (see Hematuria, [[Hematuria]])
    • Hemoglobinuria (see Hemoglobinuria, [[Hemoglobinuria]])
    • Myoglobinuria
    • Semen in Urine: results in false-positive test

Urine Bilirubin

  • Etiology of Positive Urine Bilirubin
    • Bilirubinuria
      • xxxx

Urobilinogen

  • xxxx

Urine Nitrite

  • Urinary Tract Infection (UTI)

Urine Leukocyte Esterase

  • xxxx

Urine Bacteria

  • xxx

Urine Protein (see Proteinuria, [[Proteinuria]])

  • xxxx

Urine Crystals

  • Etiology of Presence of Oxalate Crystals
    • xxxx
  • Etiology of Presence of Uric Acid Crystals
    • xxxx

Urine Microscopy

Urine Leukocytes

  • Pyuria
    • Urinary Tract Infection (UTI) (see xxxx, [[xxxx]])

References

General

  • xxx

Urine Color

  • Intravenous medications and green urine. JAMA 1981; 246: 216 [MEDLINE]
  • Clinical significance of rare and benign side effects: propofol and green urine. Pharmacotherapy 2000;20(9):1120-1122
  • Green urine after motorcycle accident. Nephrol Dial Transplant 2000;15:725-726
  • Green urine in a critically ill patient. Am J Kidney Dis 2002; 39: E20 [MEDLINE]
  • Green urine: an association with metoclopramide Nephrol Dial Transplant. 2004 Oct;19(10):2677 [MEDLINE]