Platelet Function ADP-Induced Pseudo-Negative Light Transmission (Pseudo-NLT) Test
This test measures how platelets respond to ADP, a natural substance that helps blood clots form. It helps assess whether your platelets function normally under stress, such as after injury or surgery.
["This test helps diagnose bleeding disorders or poor platelet clumping ability, which may affect wound healing or risk of excessive bleeding."]
Key facts at a glance
- LOINC
- 91124-8
- Short code
- Platelet func ADP-ind Pnl Bld Res TEG
- Synonyms
- Platelet func ADP-ind Pnl Bld Res TEG
- Category
- hematology
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 150
- Ref high
- 400
- Critical range
- 50 N/A – 1000 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- thromboelastography-resonance
- CPT
- 85049
- SNOMED
- 900000000000003003
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Why This Test Is Done
Your doctor may order this test if you have symptoms like easy bruising, prolonged bleeding from cuts, or unexplained nosebleeds. It’s also used before surgeries or procedures that could disrupt blood clotting, like dental work or joint replacements.
How the Test Works
A small sample of your whole blood is mixed with ADP and placed in a special device. The device measures how much light passes through the sample—lower light means platelets are clumping together more (normal function). If light stays high despite ADP, it suggests platelets may not respond well.
What to Expect Before the Test
No special preparation is needed. You may have a small bruise or slight discomfort where the blood sample is taken, but this is normal. Avoid aspirin or certain blood thinners for a few days before testing if your doctor advises it.
What the Results Mean
Results are compared to a standard range for healthy individuals. A result that stays high (pseudo-negative) after ADP stimulation may indicate a platelet disorder, such as von Willebrand disease or thrombocytopenia. Your doctor will discuss findings with you.
Reference range
Adult: 150-400 x 10^9/LN/A
No special preparation required. Stay well hydrated.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance
Short name
Platelet Aggregation Test (ADP-Stimulated)
Frequently asked questions
Could my test results be affected by recent medications?
What if my test shows abnormal platelet function?
Is this test the same as a standard platelet count?
Sources
- 1
- 2Lab Tests OnlineSource
- 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