II. Mechanism

  1. Urine Dipstick detects acetic acid (Acetoacetate)
    1. In Diabetic Ketoacidosis, Beta-Hydroxybutyrate (primary Ketone) is converted to Acetoacetate
  2. Confirmatory Test
    1. Urine
      1. Acetest tablet test
    2. Serum Ketone (preferred)
      1. Beta-Hydroxybutyrate
        1. Preferred Serum Ketone test
      2. Basic chemistry panel
        1. Ketoacidosis
          1. Low serum bicarbonate
          2. Increased Anion Gap
        2. Normal or resolving Ketoacidosis
          1. Normal serum bicarbonate
          2. Normal Anion Gap

III. Interpretation: Normal

  1. Negative

IV. Causes: True Positive Urine Ketones

  1. Dehydration
  2. Starvation or Low Carbohydrate Diets (Ketogenic Diet)
  3. Diabetic Ketoacidosis (DKA)
  4. Alcoholic Ketoacidosis
  5. Isopropanol toxicity
  6. Pregnancy

V. Causes: False Positive Urine Ketones

VI. Causes: False Negative Urine Ketones

  1. Delayed Urine Exam
  2. Not all Ketones (Beta-Hydroxybutyrate, Acetoacetate, Acetone) are detected by all Urine Dipstick tests
    1. Most Urine Dipsticks detect Acetoacetate

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