How long after use is ketamine (dissociative anesthetic) detectable on a urine drug screen (UDS)?

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Last updated: June 17, 2025View editorial policy

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From the Guidelines

Ketamine is typically detectable in urine drug screens for approximately 2-4 days after use. The provided evidence does not directly address the detection window of ketamine in urine drug screens 1. However, based on general medical knowledge, the detection timeframe can vary depending on several factors, including individual metabolism, kidney function, hydration status, body mass, age, and the dose consumed. For occasional users, ketamine may clear from the system more quickly, sometimes within 24-48 hours, while regular or heavy users might test positive for up to 7-14 days.

  • Factors influencing detection window:
    • Metabolism
    • Kidney function
    • Hydration status
    • Body mass
    • Age
    • Dose consumed It's essential to note that standard urine drug screens may not always test for ketamine specifically, so specialized tests may be required for detection 1. Ketamine is metabolized in the liver to norketamine and then to dehydronorketamine, which are excreted in urine. These metabolites can sometimes be detected for slightly longer periods than the parent compound. If you're concerned about ketamine detection for medical or employment purposes, it's crucial to be aware that false positives are possible with some tests, and confirmation testing may be necessary for definitive results.

From the Research

Detection Window of Ketamine in Urine

The detection window of ketamine in urine can vary depending on several factors, including the method of detection, dose, and individual metabolism.

  • According to a study published in 2005 2, ketamine was detected in urine for up to 2 days after administration using gas chromatography-mass spectrometry-negative chemical ionization (GC-MS-NCI), while its metabolite norketamine was detected for up to 14 days.
  • Another study published in 2020 3 found that ketamine and its metabolites can be detected in urine for a prolonged period, ranging from 22 to 96 days, after chronic use.
  • A study published in 2004 4 reported that the detection time of drugs of abuse, including ketamine, in urine is generally 1.5 to 4 days after a single dose, but can be longer in chronic users, up to 1 week or more.
  • A study published in 2002 5 found that ketamine can be detected in urine for 1-2 days following use.
  • Additionally, a study published in 2001 6 reported urine concentrations of ketamine and its metabolites, with ketamine concentrations ranging from 6 to 7744 ng/mL and norketamine concentrations ranging from 7 to 7986 ng/mL.

Factors Affecting Detection Window

The detection window of ketamine in urine can be influenced by various factors, including:

  • Method of detection: Different methods, such as GC-MS-NCI and liquid chromatography-mass spectrometry-atmospheric pressure chemical ionization (LC-MS-APCI), can have varying detection windows 2.
  • Dose and frequency of use: Chronic use can lead to a longer detection window 3.
  • Individual metabolism: Interindividual variation in metabolic and renal clearance can affect the detection window 4.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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