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Serum Anti-Drug Antibody (Immunoassay) - Specific to [Drug Name] (e.g., Methotrexate, Tacrolimus, etc.)

Published: August 9, 2026Updated: August 16, 2026

This test checks for antibodies your immune system may produce against certain medications you’re taking, which could affect how well they work.

Quick summary

["Some medications may not work as intended if your body develops antibodies against them."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
17640-4
Short code
S pneum Da 7F Ab 2:1 Ser IA-Rto
Synonyms
S pneum Da 7F Ab 2:1 Ser IA-Rto
Category
coagulation
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ia
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

Doctors may order this test if you’re taking medications like chemotherapy drugs, immunosuppressants, or certain heart or diabetes medications. It helps monitor whether your body is developing resistance to these treatments, which could impact your care plan.

How the Test Works

A small blood sample is taken from your arm. The sample is then tested using an immunoassay method to detect specific antibodies against the medication you’re on. This helps determine if your immune system is reacting to the drug.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to stop certain medications temporarily if instructed by your healthcare provider. Always follow their guidance to ensure accurate results.

What the Results Mean

Positive results indicate the presence of antibodies against the medication, which may suggest reduced effectiveness or potential side effects. Negative results mean no detectable antibodies were found. Your doctor will discuss these findings in the context of your treatment plan.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Anti-drug antibody test

Frequently asked questions

What does this test measure?
This test measures the presence of antibodies in your bloodstream that target specific medications you’re taking. These antibodies can interfere with how well the medication works or cause unwanted side effects.
How often should I get this test?
The frequency depends on your treatment plan and medical condition. Your doctor will determine how often you need testing, often based on how long you’ve been on the medication and your medical history.
Can I eat or drink before this test?
You can typically eat and drink normally before this test unless your doctor advises otherwise. Blood tests don’t require fasting unless specified for other reasons, like lipid panels or glucose tests.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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