Quick Facts
- Sample: Blood draw (serum)
- Fasting: No fasting required
- Turn-around: 3-4 business days. May take longer based on weather, holiday, or lab delays.
Benefits
- Stable hormone assessment - Unlike growth hormone that fluctuates daily, IGFBP-3 provides consistent readings
- No fasting required - Test anytime without dietary restrictions for maximum convenience
- Direct access - Skip doctor appointments and insurance pre-authorization delays
- Age-specific reference ranges - Accurate interpretation across all demographics and life stages
- Treatment monitoring - Track growth hormone therapy effectiveness objectively over time
Who Is This Test For?
- Adults experiencing unexplained fatigue, muscle weakness, or body composition changes
- Children with short stature, delayed growth, or suspected growth disorders
- Individuals monitoring growth hormone replacement therapy effectiveness
- People with suspected pituitary gland dysfunction or hormone imbalances
- Those with family history of growth hormone deficiency or acromegaly
- Athletes or fitness enthusiasts tracking hormone optimization naturally
How It Works – Just 3 Steps
- Order online - Select your test and schedule at a nearby lab location
- Visit the lab - Quick blood draw by certified phlebotomist, no appointment needed
- Get results - Receive results securely online within 3-4 days
FAQ
What does IGFBP-3 measure exactly? This test measures insulin-like growth factor-binding protein 3, the primary carrier protein that transports 75-90% of IGF-1 throughout your bloodstream.
How is this different from a growth hormone test? Growth hormone levels fluctuate throughout the day, while IGFBP-3 remains stable, providing a more reliable indicator of overall growth hormone function over time.
Do I need to stop any medications before testing? Most medications don't interfere, but discontinue biotin supplements 72 hours before testing to prevent assay interference.
Can I exercise before the test? Yes, normal physical activity is fine. No special preparation is needed beyond avoiding biotin supplements.
What if my results are abnormal? Abnormal results require physician consultation for clinical correlation and may indicate need for additional hormone testing or stimulation tests.
More Details
What is the purpose of this test?
The IGFBP-3 blood test evaluates your body's growth hormone production by measuring the primary carrier protein for insulin-like growth factor-1 (IGF-1). This liver-produced protein binds and transports IGF-1 throughout your body, serving as a stable indicator of growth hormone axis function (Mayo Clinic Laboratories 2018). Unlike growth hormone itself, which fluctuates dramatically throughout the day, IGFBP-3 levels remain relatively consistent, providing a reliable assessment of your integrated growth hormone activity over time (Journal of Clinical Endocrinology & Metabolism 2014).
The test employs enzyme-labeled chemiluminescent immunometric assay (ICMA) methodology, delivering 97.2% diagnostic efficiency when properly standardized to reference populations (Incyte Diagnostics 2024). This high precision makes it valuable for diagnosing growth hormone deficiency, monitoring treatment effectiveness, and assessing conditions like acromegaly or pediatric growth disorders.
Who would benefit from this test?
Adults experiencing unexplained metabolic changes benefit significantly from IGFBP-3 testing, particularly those with persistent fatigue, altered body composition, or decreased energy levels that may indicate growth hormone deficiency (PMC 12085356). The test is especially valuable for individuals seeking proactive health management without traditional healthcare barriers like physician referrals or insurance pre-authorization.
Children with growth concerns represent another key population, as IGFBP-3 testing combined with clinical evaluation provides comprehensive assessment for growth disorders (Pediatric Endocrine Society 2016). Patients receiving growth hormone therapy can use this test for objective monitoring of treatment effectiveness, while those with suspected pituitary dysfunction benefit from the stable, reliable hormone assessment it provides.
When should I order IGFBP-3 Blood Test?
Consider ordering this test when experiencing symptoms that may indicate growth hormone dysfunction, including unexplained fatigue, muscle weakness, changes in body composition, or concerns about metabolic health (Walk-In Lab 2024). The test is particularly valuable as follow-up to abnormal IGF-1 results or when seeking baseline hormone assessment for informed healthcare discussions.
Adults with suspected growth hormone deficiency should consider testing, especially those experiencing decreased energy, altered sleep patterns, or unexplained weight changes. Parents may order testing for children showing delayed growth, short stature relative to peers, or other developmental concerns that warrant hormone evaluation.
How do I interpret the results?
Results are compared to age and sex-specific reference ranges, as IGFBP-3 levels vary significantly throughout life, peaking between ages 15-25 and remaining higher in females after age 60 (Journal of Clinical Endocrinology & Metabolism 2014).
IGFBP-3 Below Normal Range
- What it means: Possible growth hormone deficiency
- Typical action: Consider additional testing, physician consultation
IGFBP-3 Within Normal Range
- What it means: Adequate growth hormone function
- Typical action: Continue routine monitoring if symptomatic
IGFBP-3 Above Normal Range
- What it means: Possible excess growth hormone (acromegaly)
- Typical action: Evaluate with IGF-1 testing, specialist referral
IGFBP-3 diagnostic efficiency reaches 92.9% when using appropriate age and sex-matched reference standards.
Disclaimer: Reference ranges may vary by laboratory. Listed ranges are general guidelines and may differ from those used by the performing lab. Always consult your healthcare provider for interpretation.
Pre-test preparation
No fasting is required for this test, allowing flexible scheduling without dietary restrictions (Mayo Clinic Laboratories 2018). However, discontinue biotin supplementation (vitamin B7/B8) at least 72 hours before specimen collection to prevent interference with the immunoassay methodology (LabCorp 2024).
Review medications with your healthcare provider, though most medications don't interfere with testing. Schedule your appointment during morning hours when laboratory processing is most efficient. Maintain normal activity levels and avoid excessive stress before testing, as these factors can influence hormone production.
How often should I get tested?
- Monitoring growth hormone therapy: Every 6–12 months
- Baseline health assessment: Every 2–3 years after age 40
- Growth disorder evaluation: As recommended by specialist
- Pituitary function monitoring: Every 12–24 months
Why early detection matters
Adult growth hormone deficiency affects 0.2 to 37.0 per 100,000 individuals in the United States, with significant underdiagnosis suspected (PMC 12085356). Early detection enables timely intervention, as treatment initiation rates for confirmed adult growth hormone deficiency remain low at only 9.7%, indicating substantial opportunity for improved patient care.
In pediatric populations, early identification of growth hormone deficiency allows for intervention during critical development windows when treatment effectiveness is maximized. The IGF-1/IGFBP-3 ratio achieves 87.5% sensitivity for growth hormone deficiency in children, offering superior diagnostic performance when identified early (Endocrine Society 2016).
Related tests you may consider
IGF-1 (Insulin-like Growth Factor-1) provides complementary assessment of growth hormone axis function, with the IGF-1/IGFBP-3 ratio offering enhanced diagnostic sensitivity for growth hormone deficiency (Endocrine Society 2016).
Growth Hormone Blood Test Panel measures HGH and IGF-1 levels in the blood to help diagnose growth hormone disorders and monitor GH treatment effectiveness.
Comprehensive Metabolic Panelprovides broader metabolic assessment to identify contributing factors to growth hormone dysfunction and establish baseline health status evaluation for optimal hormone management.
