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22797 Insulin-like Growth Factor 1

Insulin-like Growth Factor 1
Test Code: IGF1
Synonyms/Keywords
Somatomedin C​, IGF-1
Useful For
Diagnosing growth disorders, growth hormone deficiency in adults. Diagnosing and follow-up of acromegaly & gigantism.
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)
No​ Serum​ Red Top Tube (RTT)​ Serum Separator Tube (SST)​ 1.0 mL​ 0.5 mL​ 0.3 mL​
Collection Processing Instructions
Indicate age and sex on the request form. 
Deliver specimen to the lab immediately after collection.
Separate serum from blood within 60 minutes of collection.
Specimen should be frozen immediately if not to be analyzed within 24 hours of collection.
Specimen Stability Information
Specimen Type Temperature Time
Serum​ ​ ​ Refrigerated​ 24 hours​
Frozen at -20 deg Celsius​ 30 days
​Frozen at -70 deg Celsius

​1 year

Specimens should be frozen immmediately if not analyzed within 24 hours of collection or transported
to another location analysis.  Avoid repeated freeze and thaw cycles​ ​

Rejection Criteria
​Samples stored at room temperature
Gross lipemia​
​Moderate hemolysis
Interference
Hemolysis, suppresses the results by about 20%. Heterophilic antibodies in human serum can react with the immunoglobulins included in the assay components causing interference with immunoassay.
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Marshfield​ Monday and Thursday​ 1 day​ Chemiluminescent Immunometric Assay/Immulite 2000 Siemens​
Test Information

​The drug asfotase alfa (STRENSIQ), a recombinant form of alkaline phosphatase, is expected to interfere with in vitro diagnostic assays utilizing an alkaline phosphatase detection system. Test samples from patients taking asfotase alfa with a non-alkaline phosphatase methodology. ​

Reference Range Information
Age (Years)
Male
​Female
0 – 3 (>=0 days to <4)
0 -129
18-172​
4 – 6 (>=4 to <7)
22-208
​35-232
7 – 9 (>=7 to <10)
40-255
​57-277
10 – 11 (>=10 to <12)
69-316
​118-448
12 – 13 (>=12 to <14)
143-506
​170-527
14 – 15 (>=14 to <16)
177-507
​191-496
16 – 18 (>=16 to <19)
173-414
​190-429
19 – 21 (>=19 to <22)
117-323
117-323
22 – 24 (>=22 to <25)
99-289
​99-289
25 – 29 (>=25 to <30)
84-259
​84-259
30 – 34 (>=30 to <35)
71-234
​71-234
35 – 39 (>=35 to <40)
63-223
​63-223
40 – 44 (>=40 to <45)
58-219
​58-219
45 – 49 (>=45 to <50)
53-215
​53-215
50 – 54 (>=50 to <55)
48-209
​48-209
55 - 59 (>=55 to <60)
45-210
​45-210
60 – 64 (>=60 to <65)
43-220
​43-220
65 – 69 (>=65 to <70)
40-225
​40-225
70 – 79 (>=70 to <80)
35-216
​35-216
80 – 90 (>=80 to <91)
31-208
​31-208
91 and above (>=91)
No range established
​No range established
Interpretation

Blood concentrations of IGF-1 remain constant during the day and after eating. Low IGF-1 and IGFBP-3 levels are observed in GH deficiency or GH resistance. Elevated serum IGF-1 levels indicate a sustained overproduction of GH, or excessive rhGH therapy. Malnutrition results in low IGF-1 levels, which recover with restoration of adequate nutrition. Concentrations of IGF-1 increase during the first year of life reaching the highest values in early adolescent years. Normal values tend to decline progressively until age 50 years and later.

Insulin-like growth factor 1 (IGF-1) measurements can be used to assess growth hormone (GH) excess or deficiency. IGF-1 measurement has generally been shown to have superior diagnostic sensitivity and specificity, and should be used as the primary test, in particular, in the diagnosis and follow-up of acromegaly and gigantism. The combination of IGF-1 and IGFBP-3 measurements appear superior in the diagnosis of GH deficiency and resistance, and in the monitoring of recombinant human GH (rhGH) therapy.

Increased concentrations of IGF-1 are normal during pregnancy however reference ranges on this population have not been formally established. Insulin-like growth factor 1 (IGF-1) reference ranges are highly age dependent and results must always be interpreted within the context of the patient's age.

IGF-1 assays exhibit significant variability among platforms and manufacturers, therefore values obtained by different assays cannot be directly compared. If IGF-1 is being used for serial monitoring, establishing baseline of patients, it is recommended assays should not be changed. For diagnostic purposes, the results obtained from assays should always be used in combination with the clinical examination, patient medical history, and other findings.

Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
84305 ​ ​ ​ ​ ​
Synonyms/Keywords
Somatomedin C​, IGF-1
Ordering Applications
Ordering Application Description
​Cerner ​Insulin-Like Growth Factor 1
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)
No​ Serum​ Red Top Tube (RTT)​ Serum Separator Tube (SST)​ 1.0 mL​ 0.5 mL​ 0.3 mL​
Collection Processing
Indicate age and sex on the request form. 
Deliver specimen to the lab immediately after collection.
Separate serum from blood within 60 minutes of collection.
Specimen should be frozen immediately if not to be analyzed within 24 hours of collection.
Specimen Stability Information
Specimen Type Temperature Time
Serum​ ​ ​ Refrigerated​ 24 hours​
Frozen at -20 deg Celsius​ 30 days
​Frozen at -70 deg Celsius

​1 year

Specimens should be frozen immmediately if not analyzed within 24 hours of collection or transported
to another location analysis.  Avoid repeated freeze and thaw cycles​ ​

Rejection Criteria
​Samples stored at room temperature
Gross lipemia​
​Moderate hemolysis
Interference
Hemolysis, suppresses the results by about 20%. Heterophilic antibodies in human serum can react with the immunoglobulins included in the assay components causing interference with immunoassay.
Useful For
Diagnosing growth disorders, growth hormone deficiency in adults. Diagnosing and follow-up of acromegaly & gigantism.
Reference Range Information
Age (Years)
Male
​Female
0 – 3 (>=0 days to <4)
0 -129
18-172​
4 – 6 (>=4 to <7)
22-208
​35-232
7 – 9 (>=7 to <10)
40-255
​57-277
10 – 11 (>=10 to <12)
69-316
​118-448
12 – 13 (>=12 to <14)
143-506
​170-527
14 – 15 (>=14 to <16)
177-507
​191-496
16 – 18 (>=16 to <19)
173-414
​190-429
19 – 21 (>=19 to <22)
117-323
117-323
22 – 24 (>=22 to <25)
99-289
​99-289
25 – 29 (>=25 to <30)
84-259
​84-259
30 – 34 (>=30 to <35)
71-234
​71-234
35 – 39 (>=35 to <40)
63-223
​63-223
40 – 44 (>=40 to <45)
58-219
​58-219
45 – 49 (>=45 to <50)
53-215
​53-215
50 – 54 (>=50 to <55)
48-209
​48-209
55 - 59 (>=55 to <60)
45-210
​45-210
60 – 64 (>=60 to <65)
43-220
​43-220
65 – 69 (>=65 to <70)
40-225
​40-225
70 – 79 (>=70 to <80)
35-216
​35-216
80 – 90 (>=80 to <91)
31-208
​31-208
91 and above (>=91)
No range established
​No range established
Interpretation

Blood concentrations of IGF-1 remain constant during the day and after eating. Low IGF-1 and IGFBP-3 levels are observed in GH deficiency or GH resistance. Elevated serum IGF-1 levels indicate a sustained overproduction of GH, or excessive rhGH therapy. Malnutrition results in low IGF-1 levels, which recover with restoration of adequate nutrition. Concentrations of IGF-1 increase during the first year of life reaching the highest values in early adolescent years. Normal values tend to decline progressively until age 50 years and later.

Insulin-like growth factor 1 (IGF-1) measurements can be used to assess growth hormone (GH) excess or deficiency. IGF-1 measurement has generally been shown to have superior diagnostic sensitivity and specificity, and should be used as the primary test, in particular, in the diagnosis and follow-up of acromegaly and gigantism. The combination of IGF-1 and IGFBP-3 measurements appear superior in the diagnosis of GH deficiency and resistance, and in the monitoring of recombinant human GH (rhGH) therapy.

Increased concentrations of IGF-1 are normal during pregnancy however reference ranges on this population have not been formally established. Insulin-like growth factor 1 (IGF-1) reference ranges are highly age dependent and results must always be interpreted within the context of the patient's age.

IGF-1 assays exhibit significant variability among platforms and manufacturers, therefore values obtained by different assays cannot be directly compared. If IGF-1 is being used for serial monitoring, establishing baseline of patients, it is recommended assays should not be changed. For diagnostic purposes, the results obtained from assays should always be used in combination with the clinical examination, patient medical history, and other findings.

For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Marshfield​ Monday and Thursday​ 1 day​ Chemiluminescent Immunometric Assay/Immulite 2000 Siemens​
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
84305 ​ ​ ​ ​ ​
For most current information refer to the Marshfield Laboratory online reference manual.