Test Details
Insulin Like Growth Factor 1 (IGF-1)
IGF-1 is a hormone that manages the effects of growth hormone (GH) in the body. Together, IGF-1 and GH promote normal growth of bones and tissues. GH levels in the blood fluctuate throughout the day depending on diet and activity levels, but IGF-1 levels remain stable. The IGF-1 test is a useful way to find out if the body is making a normal amount of GH.
Methodology
Immunoassay
Patient Preparation
None
Preferred Specimen
1.0 mL serum (0.5 mL minimum) collected in serum separator tube (SST / Tiger Top)
Alternate Specimen
1.0 mL plasma (0.5 mL minimum) collected in white/pearl top tube
Transport Temperature
Refrigerated (ship on frozen cold packs)
Stability
- 1 day at room temperature.
- 2 days at 2-8°C.
Lab Values
Insulin Like Growth Factor 1 (IGF-1)
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IGF-1 normal ranges
The IGF-1 normal ranges are listed as 2.5th and 97.5th percentile values based on age and sex. Median values are also provided.
VIEW FEMALE REFERENCE RANGES
VIEW MALE REFERENCE RANGES
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Z-score
The z-score is the standard deviation score that enables providers to easily determine if a test result is within the range of the expected value. Further, the z-score makes results comparable with other assays.
- The values, -/+ 1.96, for the z-scores are derived from the percentiles of the standard normal distribution and correspond to the 2.5% percentile and the 97.5% percentile.
- In this respect, the z-score range between -1.96 and +1.96 corresponds to the central 95% range.
- A z-score within the range of -1.96 and +1.96 is considered normal and z-score outside this range is below respectively above the expected values.
Female Reference Ranges
| Age | Gender | Reference Range (ng/mL) | Median Value (ng/mL) |
|---|---|---|---|
| <=1 | F | 18.7-104 | 55.3 |
| 2 | F | 26.1-128 | 65.0 |
| 3 | F | 34.2-155 | 76.0 |
| 4 | F | 43.2-185 | 88.2 |
| 5 | F | 53.0-216 | 102 |
| 6 | F | 63.6-250 | 116 |
| 7 | F | 75.0-286 | 133 |
| 8 | F | 87.3-324 | 154 |
| 9 | F | 99.9-363 | 180 |
| 10 | F | 112-398 | 210 |
| 11 | F | 123-427 | 244 |
| 12 | F | 132-451 | 278 |
| 13 | F | 140-468 | 306 |
| 14 | F | 146-480 | 325 |
| 15 | F | 151-485 | 331 |
| 16 | F | 154-485 | 324 |
| 17 | F | 156-479 | 305 |
| 18 | F | 156-466 | 283 |
| 19 | F | 155-449 | 261 |
| 20 | F | 152-429 | 243 |
| 21 | F | 148-410 | 227 |
| 22 | F | 143-392 | 214 |
| 23 | F | 138-375 | 203 |
| 24 | F | 134-359 | 195 |
| 25 | F | 130-343 | 189 |
| 26 | F | 126-329 | 185 |
| 27 | F | 122-315 | 182 |
| 28 | F | 118-303 | 179 |
| 29 | F | 115-292 | 176 |
| 30 | F | 112-281 | 173 |
| 31 | F | 109-271 | 171 |
| 32 | F | 107-263 | 169 |
| 33 | F | 104-255 | 167 |
| 34 | F | 102-248 | 165 |
| 35 | F | 100-242 | 163 |
| 36 | F | 98.3-238 | 160 |
| 37 | F | 96.5-234 | 158 |
| 38 | F | 94.8-231 | 155 |
| 39 | F | 93.1-228 | 153 |
| 40 | F | 91.4-227 | 150 |
| 41 | F | 89.8-225 | 147 |
| 42 | F | 88.1-224 | 145 |
| 43 | F | 86.5-222 | 142 |
| 44 | F | 84.9-221 | 139 |
| 45 | F | 83.3-220 | 136 |
| 46 | F | 81.8-219 | 132 |
| 47 | F | 80.2-218 | 130 |
| 48 | F | 78.7-218 | 127 |
| 49 | F | 77.2-217 | 125 |
| 50 | F | 75.7-215 | 123 |
| 51 | F | 74.3-214 | 121 |
| 52 | F | 72.8-212 | 120 |
| 53 | F | 71.4-210 | 119 |
| 54 | F | 70.0-207 | 118 |
| 55 | F | 68.6-204 | 117 |
| 56 | F | 67.3-201 | 117 |
| 57 | F | 65.9-198 | 116 |
| 58 | F | 64.6-194 | 115 |
| 59 | F | 63.3-190 | 114 |
| 60 | F | 62.0-186 | 113 |
| 61 | F | 60.7-182 | 112 |
| 62 | F | 59.5-179 | 111 |
| 63 | F | 58.3-176 | 110 |
| 64 | F | 57.3-173 | 109 |
| 65 | F | 56.3-170 | 108 |
| 66 | F | 55.5-168 | 106 |
| 67 | F | 54.8-166 | 105 |
| 68 | F | 54.2-164 | 104 |
| 69 | F | 53.8-163 | 102 |
| 70 | F | 53.5-162 | 101 |
| 71 | F | 53.3-161 | 99.8 |
| 72 | F | 53.2-160 | 98.7 |
| 73 | F | 53.2-160 | 97.6 |
| 74 | F | 53.3-160 | 96.7 |
| 75 | F | 53.5-160 | 95.8 |
| 76 | F | 53.7-161 | 95.1 |
| 77 | F | 54.0-162 | 94.4 |
| 78 | F | 54.3-163 | 93.9 |
| 79 | F | 54.7-164 | 93.4 |
| 80 | F | 55.1-166 | 93.0 |
Male Reference Ranges
| Age | Gender | Reference Range (ng/mL) | Median Value (ng/mL) |
|---|---|---|---|
| <=1 | M | 11.8-96.4 | 44.4 |
| 2 | M | 13.9-104 | 51.7 |
| 3 | M | 18.9-116 | 60.5 |
| 4 | M | 26.8-134 | 70.6 |
| 5 | M | 36.6-156 | 81.9 |
| 6 | M | 47.1-184 | 94.5 |
| 7 | M | 57.5-216 | 108 |
| 8 | M | 67.5-254 | 123 |
| 9 | M | 76.9-296 | 141 |
| 10 | M | 85.7-343 | 164 |
| 11 | M | 93.9-392 | 194 |
| 12 | M | 101-434 | 231 |
| 13 | M | 108-467 | 270 |
| 14 | M | 115-489 | 304 |
| 15 | M | 120-501 | 327 |
| 16 | M | 125-503 | 339 |
| 17 | M | 129-495 | 340 |
| 18 | M | 132-476 | 331 |
| 19 | M | 134-450 | 312 |
| 20 | M | 136-421 | 291 |
| 21 | M | 137-394 | 272 |
| 22 | M | 137-370 | 254 |
| 23 | M | 136-348 | 238 |
| 24 | M | 135-328 | 225 |
| 25 | M | 132-310 | 213 |
| 26 | M | 130-295 | 203 |
| 27 | M | 128-282 | 194 |
| 28 | M | 125-271 | 188 |
| 29 | M | 123-263 | 183 |
| 30 | M | 120-257 | 180 |
| 31 | M | 118-253 | 176 |
| 32 | M | 116-250 | 173 |
| 33 | M | 114-247 | 170 |
| 34 | M | 111-244 | 166 |
| 35 | M | 109-242 | 163 |
| 36 | M | 107-239 | 160 |
| 37 | M | 105-236 | 158 |
| 38 | M | 103-234 | 155 |
| 39 | M | 101-231 | 152 |
| 40 | M | 98.5-229 | 150 |
| 41 | M | 96.4-226 | 148 |
| 42 | M | 94.4-223 | 146 |
| 43 | M | 92.4-221 | 144 |
| 44 | M | 90.5-218 | 142 |
| 45 | M | 88.5-216 | 140 |
| 46 | M | 86.5-214 | 139 |
| 47 | M | 84.6-211 | 137 |
| 48 | M | 82.6-209 | 136 |
| 49 | M | 80.6-207 | 135 |
| 50 | M | 78.7-205 | 133 |
| 51 | M | 76.7-203 | 132 |
| 52 | M | 74.8-201 | 130 |
| 53 | M | 72.8-200 | 129 |
| 54 | M | 70.9-198 | 127 |
| 55 | M | 68.9-196 | 126 |
| 56 | M | 67.0-195 | 124 |
| 57 | M | 65.3-194 | 122 |
| 58 | M | 63.7-193 | 121 |
| 59 | M | 62.3-192 | 119 |
| 60 | M | 61.1-191 | 118 |
| 61 | M | 60.0-190 | 117 |
| 62 | M | 59.2-189 | 116 |
| 63 | M | 58.5-188 | 116 |
| 64 | M | 57.9-188 | 115 |
| 65 | M | 57.4-187 | 115 |
| 66 | M | 56.8-186 | 115 |
| 67 | M | 56.3-186 | 115 |
| 68 | M | 55.8-185 | 115 |
| 69 | M | 55.2-185 | 114 |
| 70 | M | 54.7-185 | 114 |
| 71 | M | 54.1-184 | 113 |
| 72 | M | 53.6-184 | 111 |
| 73 | M | 53.0-184 | 110 |
| 74 | M | 52.4-184 | 108 |
| 75 | M | 51.9-184 | 106 |
| 76 | M | 51.3-184 | 104 |
| 77 | M | 50.7-184 | 102 |
| 78 | M | 50.2-184 | 99 |
| 79 | M | 49.6-184 | 96.1 |
Clinical Significance
Insulin Like Growth Factor 1 (IGF-1)
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Very Low Values
Very low values are associated with growth hormone deficiency and short stature in children and adolescents (<17 years of age). Very low IGF-1 has also been associated with fatty liver disease, liver fibrosis, increased risk of diabetes and heart failure in adults.
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Very High Values
Very high values are associated with growth hormone excess and acromegaly, as well as delayed puberty, pregnancy, hyperthyroidism, and high protein diets.
Treatment Options
Insulin Like Growth Factor 1 (IGF-1)
Treatment for Low IGF-1 Levels:
Low IGF-1 levels are often related to growth hormone (GH) deficiency, which can occur due to pituitary gland issues or other underlying conditions.
Growth Hormone Therapy:
- Human Growth Hormone (HGH) Replacement: Administering synthetic HGH can help increase IGF-1 levels. It’s typically given as a daily injection and is used in children with growth failure or adults with GH deficiency.
Managing Underlying Conditions:
- If a medical condition like hypothyroidism or malnutrition is causing low IGF-1, treating the underlying issue may help restore IGF-1 levels.
Diet and Lifestyle Adjustments:
- Adequate nutrition and managing stress levels can positively affect IGF-1 levels. Consuming sufficient protein and essential nutrients is key to supporting normal growth factor production.
IGF-1 Replacement Therapy:
- In rare cases, direct IGF-1 therapy (Mecasermin) may be prescribed for children with severe IGF-1 deficiency who do not respond well to GH therapy.
Treatment for High IGF-1 Levels:
Elevated IGF-1 is often associated with conditions like acromegaly (usually due to excess GH secretion, often caused by a pituitary tumor).
Surgical Treatment (Pituitary Tumor):
- If a pituitary tumor is causing excessive GH and IGF-1 production, surgery to remove the tumor (transsphenoidal surgery) is the first-line treatment.
Medication:/strong>
- Somatostatin Analogues (e.g., Octreotide, Lanreotide): These drugs inhibit GH secretion and help reduce IGF-1 levels.
- GH Receptor Antagonists (e.g., Pegvisomant): These block GH receptors and reduce IGF-1 production.
- Dopamine Agonists (e.g., Cabergoline): Sometimes used to control GH secretion, particularly in combination with other therapies.
Radiation Therapy:
- If surgery and medications are insufficient, radiation therapy may be used to target the pituitary gland and reduce tumor size, ultimately lowering IGF-1 levels.
Regular Monitoring:
- For both low and high IGF-1, regular monitoring of IGF-1 and GH levels, along with other hormonal assessments, is important to track treatment progress and adjust therapy as needed.
It’s essential to work with an endocrinologist for proper diagnosis and to design a treatment plan specific to the underlying cause.
