Serum Soybean Trypsin Inhibitor (SBTI) Concentration
This test measures the amount of soybean trypsin inhibitor, a naturally occurring protein in serum that can interfere with certain blood tests, such as those for thyroid hormones or other immunoassays.
["SBTI can sometimes affect lab results and may require additional testing or adjustments by your healthcare provider."]
Key facts at a glance
- LOINC
- 63476-6
- Short code
- Soybean (rGly m) 4 IgE Qn
- Synonyms
- Soybean (rGly m) 4 IgE Qn
- Category
- glucose
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- 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 Is This Test Done?
Your doctor may order this test if you have received soybean-based products (like soy milk, soy protein supplements, or certain medications) and your blood test results appear abnormal. It helps identify whether the soybean components are causing interference with lab tests.
How Is the Sample Collected?
A blood sample is drawn from a vein, usually in your arm. The blood is then processed into serum (the liquid part after clotting). This test is typically performed on serum.
What Does a High or Low Level Mean?
Elevated levels of soybean trypsin inhibitor may indicate recent exposure to soybean products, which can temporarily alter the results of certain immunoassays. Low levels are less commonly significant unless further clinical context is provided.
Common Causes of Abnormal Results
Consuming soy-based foods, supplements, or medications shortly before testing can lead to higher levels of soybean trypsin inhibitor. This is not a health concern in itself but may require retesting or clarification of results by your healthcare provider.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
SBTI can bind to certain antibodies or enzymes used in immunoassays, potentially causing false-positive or false-negative results for tests like thyroid-stimulating hormone (TSH), prolactin, or other hormone assays. This is particularly relevant if you’ve recently consumed soy products or taken soy-containing supplements.
Short name
SBTI Level
Frequently asked questions
Why might my doctor ask for this test?
What should I do if I recently ate soy products before my test?
No, this test is not a standalone diagnostic tool. It’s used to investigate potential interference from soybean products in lab results. If your doctor suspects another condition, they may order additional tests.
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