Acetamincryurnsqlmicro
This test examines urine sediment under a microscope to detect acetaminophen crystals, which may indicate drug overdose or kidney-related complications.
{"The test looks for crystals from pain reliever (acetaminophen/ Tylenol) in your urine","Crystals may appear if you took too much acetaminophen or have kidney problems","A positive result requires immediate medical attention","The test uses a simple urine sample analyzed under a microscope","Results help doctors assess drug toxicity and kidney function"}
Key facts at a glance
- LOINC
- 43628-7
- Short code
- ACET-URINE
- Synonyms
- Acetamin Cry UrnS Ql Micro
- Category
- chemistry
- Sample
- urine
- Container
- Sterile urine container (clean catch or catheter specimen)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 0 years
- Method
- microscopy-light
- CPT
- 81001
- SNOMED
- 271457004
- Specimen volume
- 10-50 mL preferred
- Stability
- Room temperature: 2-4 hours; Refrigerated (2-8°C): 24-48 hours; Do not freeze
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
What is this test?
The Acetaminophen Crystals test is a urine analysis that uses light microscopy to detect the presence of acetaminophen crystals in urine sediment. Acetaminophen (also known as paracetamol or Tylenol) is a common over-the-counter pain reliever and fever reducer. When taken in excessive amounts, the body cannot process all of it, and crystal formations may appear in the urine. This test helps healthcare providers identify potential acetaminophen overdose or drug-related kidney complications.
How is the test performed?
A urine sample is collected, typically using a clean-catch method. The sample is then centrifuged to separate the solid particles (sediment) from the liquid. The sediment is examined under a microscope by a lab technician who looks for characteristic crystal formations that indicate acetaminophen exposure. The result is reported as either 'present' or 'absent.'
Why might I need this test?
Your doctor may order this test if you have symptoms of acetaminophen overdose, such as nausea, vomiting, abdominal pain, or confusion. It may also be ordered if you have signs of kidney problems, or if you are being monitored after taking large amounts of acetaminophen. The test is part of evaluating drug-induced kidney injury.
How should I prepare?
No special preparation is needed. You should inform your doctor about all medications, supplements, and over-the-counter drugs you have recently taken, including acetaminophen products. Drink plenty of water before the test to ensure an adequate urine sample.
Reference range
Not detected (Negative)N/A
Collect midstream clean-catch urine specimen in a sterile container. Female patients should cleanse the urethral area before collection. No special preparation required.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Frequently asked questions
Is this test painful?
What does a positive result mean?
Can I have crystals even with normal acetaminophen use?
How long does it take to get results?
Do I need to fast before this test?
Sources
- 1
- 2
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy