Challenge
Key facts at a glance
- LOINC
- 15334-6
- Short code
- CHAL
- Synonyms
- —
- Category
- chemistry
- Sample
- serum
- Container
- Serum separator tube (SST) or red-top tube without anticoagulant
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Varies by specific challenge protocol; typically involves baseline measurement followed by administration of a provocative agent (e.g., glucose, lactose, ACTH, histamine) and serial serum sampling for analyte quantification
- CPT
- Varies by specific challenge test (e.g., 80400 for ACTH stimulation, 82950 for glucose tolerance, 82951 for GTT with insulin, 82952 for GTT each additional specimen)
- SNOMED
- 40274000 | Laboratory challenge test
- Specimen volume
- 2-5 mL of whole blood; serial samples may require additional volume depending on number of time points
- Stability
- Serum stability is analyte-dependent. Most serum analytes are stable for 24 hours at room temperature, 7 days at 2-8°C, and longer when frozen at -20°C or below. Process per specific analyte requirements.
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Reference range
Reference ranges are challenge-specific and depend on the analyte being measured and the type of provocative test performed. Interpret results in the context of the specific challenge protocol and the patient's clinical presentation.N/A
Preparation requirements vary by challenge type. Many challenges require fasting for 8-12 hours prior to baseline collection. Patients should remain at rest during the test. Specific medications may need to be withheld per protocol. Confirm pre-test requirements with ordering physician.
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