1,25-dihydroxyvitamin D (Calcitriol)
This test measures 1,25-dihydroxyvitamin D, the biologically active form of vitamin D. It is used to investigate calcium imbalance, kidney disease and...
IGF-1 (Somatomedin)
140.99
The IGF-1 test measures insulin-like growth factor-1 in the blood. It reflects average growth hormone activity over time.
Turnaround time
1 day
Biomarkers count
1
Same-Day Appointments
UKAS Accredited Labs
Book your test
Under 18? Patients under 18 can only be seen at GB Medlabs and Clinilabs, Monday to Friday only.
1
Email
2
Service
3
Details
4
Confirm
{{ emailError }}
Choose Service Type
Home visit
Professional phlebotomist comes to you
+ £{{ home_visit_fee }}
In clinic
Visit our clinic for your test
{{ clinic_visit_fee > 0 ? '+ £' + clinic_visit_fee : 'Free' }}
Home Visit Details
{{ homeAddressError }}
Home visits require at least 24 hours notice.
{{ homeTimeError }}
Choose Clinic Option
Select a clinic:
{{ clinic.name }}
{{ clinic.full_address }}
{{ selectedClinic.name }}
{{ selectedClinic.full_address }}
Select a date
{{ timeSlotAlert }}
Select an hour
Available time slots: {{ timeSlots.length}}
{{ slot.preview }}
{{ selectedTime.preview }}
Loading add-ons...
{{ addOnError }}
No recommended add-ons available.
×
{{ addon.name }}
£{{ addon.price }}
{{ addon.excerpt }}
Selected
Selected ({{ selectedAddOns.length }})
£{{ addOnsTotal }}
- {{ sa.name }} £{{ sa.price }}
Included in total above.
Details about IGF-1 (Somatomedin)
What is the IGF-1 (Somatomedin) test?
The IGF-1 (Insulin-Like Growth Factor-1) test measures the level of IGF-1, a hormone mainly produced by the liver in response to growth hormone (GH) secretion from the pituitary gland. IGF-1 mediates many of the biological effects of growth hormone, including tissue growth, cell repair, and metabolism.
Unlike growth hormone itself, which fluctuates significantly throughout the day, IGF-1 levels remain relatively stable. This makes IGF-1 a reliable indicator of average growth hormone activity.
The test is widely used in endocrinology to evaluate disorders of growth hormone excess or deficiency in both adults and children.
Why do I need an IGF-1 test?
Abnormal IGF-1 levels can indicate disrupted growth hormone regulation, which may affect growth, metabolism, muscle mass, and overall health.
You may need an IGF-1 test if you:
- Have symptoms of growth hormone deficiency
- Have suspected growth hormone excess
- Have unexplained fatigue or weakness
- Experience changes in body composition
- Have joint pain or enlarged hands/feet
- Are being investigated for pituitary disorders
- Have abnormal growth patterns (children or adolescents)
- Are monitoring treatment for GH-related conditions
Conditions commonly investigated with IGF-1 include:
- Growth hormone deficiency
- Acromegaly
- Gigantism (children)
- Pituitary adenomas
Benefits of the IGF-1 (Somatomedin) test
- Reflects long-term growth hormone activity
More stable than direct GH testing. - Supports diagnosis of acromegaly
Elevated levels are a key diagnostic marker. - Identifies growth hormone deficiency
Useful in adults and children. - Assists pituitary disorder assessment
Supports endocrine investigations. - Clinically established endocrine marker
Used in NHS and specialist care. - Useful for treatment monitoring
Tracks response to GH therapy or surgery. - Single blood sample
Simple and convenient testing. - Reliable and reproducible
Minimal daily variation.
Step by step – how the test works
You can access IGF-1 testing UK-wide through two options:
- Clinic appointment
Attend your nearest UK clinic, where a healthcare professional will take your blood sample. - At-home or hotel visit (£60 extra)
A qualified phlebotomist comes to your home or hotel for blood collection.
Your sample is analysed in an accredited UK laboratory, and results are delivered securely.
Your results explained
Low IGF-1 levels
May indicate growth hormone deficiency, malnutrition, liver disease, or chronic illness.
Typical UK interpretation:
- Below age-adjusted reference range
Normal IGF-1 levels
Suggest normal growth hormone secretion and endocrine balance.
Typical UK interpretation:
- Within age-adjusted reference range
High IGF-1 levels
May indicate growth hormone excess, most commonly seen in acromegaly.
Typical UK interpretation:
- Above age-adjusted reference range
IGF-1 reference ranges are strongly age-dependent and must be interpreted accordingly.
How It Works
Simple steps to get your results
1
Book Online
Choose your test online and book in seconds. Select your preferred clinic location or home visit option.
2
Visit or Test at Home
Attend one of our UK or London clinics, arrange a home nurse visit, or use a finger-prick kit where available.
3
Get Your Results
Your sample is analysed by accredited UK laboratories, with secure results delivered directly to you.
Take control of your health with London Blood Tests
WhatsApp UsHow to Prepare for Your Test
Follow these guidelines for accurate results
Sample Timing
Where possible, attend your blood test between 7am and 12pm. Please wait until any short-term illness or infection has fully resolved before testing. Avoid intense exercise for 24–48 hours beforehand, as this can affect certain markers.
Fasting & Hydration
Fasting is not always required, but some tests may recommend it. If fasting is advised, avoid food for 8–12 hours before your appointment and drink water only. Stay well hydrated, as this helps with sample collection and accuracy.
Medications & Supplements
Continue prescribed medications unless advised otherwise by your clinician. Avoid vitamin, mineral, or biotin supplements for at least 24–48 hours before your test, as these can interfere with results. If you are unsure about any medication or supplement, please let us know before your appointment.
Hormones & Menstrual Cycle
For hormone-related tests, timing within your menstrual cycle may be important. If relevant, follow any specific guidance provided on your test page.
If you have any questions or special circumstances, our team is happy to advise before your appointment.
Frequently Asked Questions
Because IGF-1 reflects average GH activity and does not fluctuate hourly.
Fasting is often recommended; follow booking instructions.
Yes. Levels peak in adolescence and decline with age.
Yes. It is the primary screening test.
Yes. The liver produces IGF-1.
Yes, especially in growth assessment.
Yes. It is commonly used for follow-up.
Some hormonal treatments can influence levels.
Yes. Home or hotel phlebotomy is available UK-wide for £60 extra.
Yes. Endocrine interpretation is recommended.
Similar Products in Blood Testing
Discover more options in this category:
17-Hydroxyprogesterone
This test measures 17-hydroxyprogesterone, a hormone involved in cortisol production. It is used to assess adrenal function and diagnose congenital ad...
5 HIAA
The 5-HIAA (5-Hydroxyindoleacetic Acid) blood test measures the amount of 5-HIAA, a breakdown product of serotonin, in the bloodstream. Elevated level...
6-Thioguanine Nucleotides
This test measures 6-thioguanine nucleotide levels to monitor thiopurine medications. It helps optimise treatment effectiveness while reducing toxicit...
7 Sexually Transmitted Infections by PCR
This PCR screen detects seven common sexually transmitted infections with high accuracy. It identifies active infections even when symptoms are mild o...