Ketostix: instrumental analysis 101

V_Keto_V Posts: 342 Member
According to Lexicomp: Ketostix for ketone urinalysis utilizing Nitroprusside (i.e. Color change) is not reliable for detection of Beta Hydroxybutyric acid, the ketone which compromises about 80% of total ketones when someone is in a state of Ketosis. However, Ketostix do reliably measure Acetic acetate (about 20% of total ketones). A fasted state of ketosis is typically achieved after 18 hours of fasting. Large rises in urinary ketones are detectable prior to serum ketone level elevations.

False (+)s: N-acetyl cysteine (NAC), Levodopa (L-DOPA), Ascorbic acid (megadoses of Vitamin C), Isopropanol (2-propanol for you chemistry geeks), Valproic Acid (VPA)/Divalproex (DPA), Phen-AZO-pyridine (PYRIDIUM/AZO), & Phthaleins

Thought you fellow Keto'ers would like to know some limitations of Ketostix as well as having reassurance from not achieving Ketosis according to a simple chemical reaction.


  • ChoiceNotChance
    ChoiceNotChance Posts: 644 Member
    Agreed. There is so much information out there stating the inaccuracy of Ketostix- I'm suprised so many still use them.
  • Bob314159
    Bob314159 Posts: 1,178 Member
    And I just bought my first package :s
  • missmaddygal
    missmaddygal Posts: 6 Member
    Even with their limitations there is something very satisfying about that colour change!
  • V_Keto_V
    V_Keto_V Posts: 342 Member
    Yes, the color change (not necessarily the quantity corresponding to color) can be indicative of someone being in Ketosis or not.

    More limitations include exercise, excess fasting, & energy can test negative for urinary ketones because they have all been excreted or have partitioned into the blood (again there will be a dramatic rise in urinary ketones before blood ketones will get a False (-) should you measure exercise too much, fast too long, or over diurese/over hydrate diluting urine, etc.)