Montelukast-Dependent Platelet-Associated IgM Antibodies, Serum/Plasma — Qualitative by Flow Cytometry
Detects platelet-associated IgM antibodies that react with montelukast, which may help evaluate suspected immune-mediated thrombocytopenia.
["A positive result may support a montelukast-associated immune platelet reaction when low platelets and other findings support the diagnosis."]
Key facts at a glance
- LOINC
- 73258-6
- Short code
- Montelukast ind plt IgM SerPl Ql FC
- Synonyms
- Montelukast ind plt IgM SerPl Ql FC
- Category
- liver
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 10
- Ref high
- 40
- Critical range
- — – 500 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- flow-cytometry
- CPT
- 84484
- SNOMED
- 302774002
- 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
What is this test?
This blood test looks for IgM antibodies attached to platelets that react when the drug montelukast is present. It is used in selected cases of suspected drug-induced immune thrombocytopenia, a condition in which the immune system damages platelets.
Why might I need this test?
Your clinician may order it if platelet counts became unusually low after starting montelukast or another leukotriene receptor antagonist. It may be considered alongside your medication history, symptoms, and other laboratory results.
How is the test performed?
A blood sample is collected and examined by flow cytometry to determine whether montelukast-dependent platelet-associated IgM is present. The result is reported as positive, negative, or sometimes indeterminate.
How do I prepare for the test?
No special preparation is usually required beyond following your clinician's instructions. Tell your care team which medicines you take and when montelukast was started; do not stop or change any medication without medical advice.
Reference range
Adult: 10-40 U/LN/A
No special preparation required. Avoid fatty meals before the test if possible.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
A positive result indicates that platelet-associated IgM reacts in the presence of montelukast. In a compatible clinical setting, this may support a montelukast-associated immune platelet reaction, but the result should be interpreted with the medication history, platelet count, symptoms, and other tests. A negative or indeterminate result does not completely exclude a drug-induced reaction.
Short name
Montelukast-Dependent Platelet IgM Antibodies
Frequently asked questions
Does a positive result mean I definitely have a bleeding disorder?
Can I take montelukast while waiting for the result?
What if the result is negative but my platelet count is low?
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 17, 2026. · Read our editorial policy