Test Details
Methodology
Immunochemiluminometric assay (ICMA)
Result Turnaround Time
2 - 4 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Use
The IDS-iSYS Insulin-like Growth Factor-I (IGF-I) assay is an in vitro diagnostic device intended for the quantitative determination of IGF-I in human serum or plasma on the IDS system. Results are to be used in conjunction with other clinical and laboratory data to assist the clinician in the assessment of growth disorders.
Special Instructions
This test may exhibit interference when sample is collected from a person who is consuming a supplement with a high dose of biotin (also termed as vitamin B7 or B8, vitamin H, or coenzyme R). It is recommended to ask all patients who may be indicated for this test about biotin supplementation. Patients should be cautioned to stop biotin consumption at least 72 hours prior to the collection of a sample.
Limitations
Malnutrition will cause low somatomedin-C levels in spite of normal amounts of circulating growth hormone. The Sm-C level does not distinguish pituitary dwarfism from constitutional delay of growth and development.2
Custom Additional Information
IGF-1 is a relatively small peptide (molecular weight 7647) that is tightly bound in serum to one of several high affinity binding proteins.1 IGF-1 has approximately 50% sequence homology with proinsulin and has a number of biological activities similar to insulin. IGF-1 is a hormone that serves as the major effector of GH-stimulated somatic growth, as well as GH-independent anabolic responses in numerous tissues. IGF-1 has numerous growth-promoting effects, including mitogenic effects and the promotion of cartilage sulfation. Measurement of serum IGF-1 has been widely used in the diagnosis of disorders of GH secretion,2-6 management of disorders that lead to nutritional insufficiency, or catabolism,7-9 and monitoring both GH and IGF-1 replacement therapy. IGF-1 measurement may also have a role in the physiology of malignant disease.10,11
The IDS iSYS IGF-1 assay conforms to the recommendations outlined in the recently published consensus statement on the standardization and evaluation of IGF-1 assays.12 The assay is calibrated to the WHO recombinant reference standard 02/254 for IGF-1.13 Reference intervals for IGF-I using the IDS IGF-I were determined in a clinical routine study population from the United States.13,14 The cohort included 778,173 males and 710,752 females, aged from 0 to 90 years, who were representative of the overall United States population in terms of gender, race and ethnicity. Reference intervals were adjusted for age and sex using a modified Hoffman approach.15
Specimen Requirements
Specimen
Serum
Volume
0.5 mL
Minimum Volume
0.2 mL (Note: This volume does not allow for repeat testing.)
Container
Red-top tube or gel-barrier tube
Collection Instructions
Separate serum from cells. Transfer separated serum to a plastic transport tube. Please include the patient's age on the test request form.
Stability Requirements
Temperature
Period
Room temperature
3 days
Refrigerated
7 days
Frozen
90 days
Freeze/thaw cycles
Stable x3
Reference Range
See table.1
Insulin-like Growth Factor 1 (IGF-1)
Age
(y)
Male
(ng/mL)
Female
(ng/mL)
Age
(y)
Male
(ng/mL)
Female
(ng/mL)
<1
18−79
14−106
18
145−506
117−430
1
20−108
23−136
19
122−435
113−408
2
24−135
30−163
20
116−410
108−384
3
28−148
34−192
21 to 25
109−353
101−347
4
32−165
38−217
26 to 30
101−307
91−308
5
37−196
46−243
31 to 35
95−290
84−281
6
43−229
56−268
36 to 40
90−278
79−259
7
50−243
64−288
41 to 45
84–270
74−239
8
59−275
74−337
46 to 50
81−263
70−225
9
67−315
81−405
51 to 55
74-−255
65−216
10
75−366
85−526
56 to 60
68−247
60−207
11
82−423
91−610
61 to 65
64−240
57−202
12
87−519
110−656
66 to 70
59−230
52−196
13
101–620
150–678
71 to 75
53−222
48−191
14
123−701
174−656
76 to 80
45−207
42−185
15
161−760
156−586
81 to 85
40−194
39−177
16
171−748
140−517
86 to 90
33−176
34−169
17
161−635
130−471
>90
Not established
Not established
Storage Instructions
Refrigerate.
Causes for Rejection
Plasma specimen
References
Daughaday WH, Hall K, Salmon WD Jr, Van den Brande JL, Van Wyk JJ. On the nomenclature of the somatomedins and insulin-like growth factors. J Clin Endocrinol Metab. 1987 Nov;65(5):1075-1076.3667879
DeGroot LJ, Jameson JL, eds. Endocrinology. 4th ed. Philadelphia, Pa: WB Saunders Co; 2001:2257-2268.
Pearson OH, Arafah B, Brodkey J. Management of acromegaly. Ann Intern Med. 1981 Aug;95(2):225-227.7258874
Pintor C, Loche S, Cella SG, Müller EE, Baumann G. A child with phenotypic Laron dwarfism and normal somatomedin levels. N Engl J Med. 1989 Feb 9;320(6):376-379.2913494
Rappaport R, Prevot C, Brauner R. Somatomedin-C and growth in children with precocious puberty: a study of the effect of the level of growth hormone secretion. J Clin Endocrinol Metab. 1987 Dec;65(6):1112-1117.3680478
Underwood LE, D'Ercole AJ. Anterior pituitary gland and hypothalamus: Disorders affecting anterior pituitary function. In: Rudolph AM, Hoffman JI, eds. Pediatrics. 18th ed. Norwalk, Conn: Appleton & Lange; 1987:1454-1465.
Watts NB, Keffer JH. Anterior pituitary and hypothalamus. Practical Endocrinology. 4th ed. Philadelphia, Pa: Lea & Febiger; 1989:11-36.
Footnotes
1. Holly JM, Perks CM. Insulin-like growth factor physiology: What we have learned from human studies. Endocrinol Metab Clin North Am. 2012 Jun;41(2):249-263.22682629
2. Clemmons DR. Clinical laboratory indices in the treatment of acromegaly. Clin Chim Acta. 2011 Feb 20;412(5-6):403-409.21075098
3. Melmed S, Colao A, Barkan A, et al. Guidelines for acromegaly management: An update. J Clin Endocrinol Metab. 2009 May;94(5):1509-1517.19208732
4. Katznelson L, Atkinson JL, Cook DM, et al. American Association of Clinical Endocrinologists medical guidelines for clinical practice for the diagnosis and treatment of acromegaly--2011 update. Endocr Pract. 2011 Jul-Aug;17(Suppl 4):1-44.21846616
5. Molitch ME, Clemmons DR, Malozowski S, Merriam GR, Vance ML; Endocrine Society. Evaluation and treatment of adult growth hormone deficiency: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2011 Jun;96(6):1587-1609.21602453
6. Cook DM, Yuen KC, Biller BM, Kemp SF, Vance ML; American Association of Clinical Endocrinologists. American Association of Clinical Endocrinologists medical guidelines for clinical practice for growth hormone use in growth hormone-deficient adults and transition patients−2009 update. Endocr Pract. 2009 Sep-Oct;15(Suppl 2):1-29.20228036
7. Friedrich N, Thuesen B, Jrgensen T, et al. The association between IGF-I and insulin resistance: A general population study in Danish adults. Diabetes Care. 2012 Apr;35(4):768-773.22374641
8. Kreitschmann-Andermahr I, Suárez P, Jennings R, Evers N, Brabant G. GH/IGF-I regulation in obesity--mechanisms and practical consequences in children and adults. Horm Res Peadiatr. 2010;73(3):153-160.20197666
9. Clemmons DR. Metabolic actions of insulin-like growth factor-I in normal physiology and diabetes. Endocrinol Metab Clin North Am. 2012 Jun;41(2):425-443, vii-viii.22682639
10. Endogenous Hormones and Breast Cancer Collaborative Group, Key TJ, Appleby PN, Reeves GK, Roddam AW. Insulin-like growth factor 1 (IGF1), IGF binding protein 3 (IGFBP3), and breast cancer risk: Pooled individual data analysis of 17 prospective studies. Lancet Oncol. 2010 Jun;11(6):530-542.20472501
11. Khosravi J, Diamandi A, Mistry J, Scorilas A. Insulin-like growth factor I (IGF-I) and IGF-binding protein-3 in benign prostatic hyperplasia and prostate cancer. J Clin Endocrinol Metab. 2001 Feb;86(2):694-699.11158033
12. Clemmons DR. Consensus statement on the standardization and evaluation of growth hormone and insulin-like growth factor assays. Clin Chem. 2011 Apr;57(4):555-559.21285256
13. IDS-iSYS Insulin-like Growth Factor-I (IGF-I) [instructions for use]. Boldon, UK: Boldon, Tyne & Wear, 2020.
14. Bidlingmaier M, Valcour A, Schilbach K, et al. Differences in the Distribution of IGF-I Concentrations Between European and US Populations. J Endocr Soc. 2022 May 19;6(7):bvac081.35673402
15. Katayev A, Fleming JK, Luo D, Fisher AH, Sharp TM. Reference intervals data mining: no longer a probability paper method. Am J Clin Pathol. 2015 Jan;143(1):134-142.25511152
LOINC® Map
Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC 010363 IGF-1 2484-4 010369 Insulin-Like Growth Factor I ng/mL 2484-4 Order Code 010363 Order Code Name IGF-1 Order Loinc 2484-4 Result Code 010369 Result Code Name Insulin-Like Growth Factor I UofM ng/mL Result LOINC 2484-4