{"id":"igf-1-z-score","name":"IGF-1 Z-Score (SDS)","shortName":"IGF-1 Z-score","aliases":["IGF-1 Z Score","IGF-I SDS","IGF-1 SD Score","IGF-1 Standard Deviation Score","IGF-1 Z Score (Age/Sex)","IGF-I Z Score","IGF-1, Z Score","IGF 1 Z SCORE CALCULATION","IGF-1 SDS","IGF-1 Z-Score (SD)","Insulin-like Growth Factor-I Z-Score"],"abbreviations":["IGF-1 SDS","IGF-I SDS"],"loinc":[{"code":"73561-3","primary":true}],"specimen":"calculated","units":[{"ucum":"{SD}","display":"SD"}],"referenceRanges":[{"population":"Adults","low":-2,"high":2,"unit":"{SD}","unitDisplay":"SD","note":"Quest prints -2.0 to +2.0 SD for men and for women on its IGF-1 LC/MS test. ARUP states that a result inside its IGF-1 reference interval has a Z-score between -2.0 and +2.0. Each lab calculates the score from its own reference data, so it applies only to the IGF-1 result printed with it. ARUP's calculation is limited to ages 85 and under. For children, Labcorp reports Z-scores by Tanner stage. A 2024 review says a low IGF-1 (below -2 SDS) alone is not enough to diagnose growth hormone deficiency in adults with fewer than two other pituitary hormone deficits, and Mayo describes treatment aims inside the range (middle to upper third for growth hormone replacement, lower third for treated acromegaly).","sources":[{"title":"IGF-1, LC/MS (test code 16293)","url":"https://testdirectory.questdiagnostics.com/test/test-detail/16293/?cc=MASTER","publisher":"Quest Diagnostics"},{"title":"Insulin-Like Growth Factor 1 (IGF-1) with Calculated Z-Score (ARUP test 2007698)","url":"https://ltd.aruplab.com/Tests/Pub/2007698","publisher":"ARUP Laboratories"},{"title":"A 2024 Update on Growth Hormone Deficiency Syndrome in Adults: From Guidelines to Real Life","url":"https://pmc.ncbi.nlm.nih.gov/articles/PMC11508958/","publisher":"Journal of Clinical Medicine","year":2024},{"title":"IGFB3: Insulin-Like Growth Factor-Binding Protein 3, Serum","url":"https://www.mayocliniclabs.com/test-catalog/overview/83300","publisher":"Mayo Clinic Laboratories"}]}],"review":{"status":"ai-verified","label":"AI-verified against cited sources. Awaiting expert review","lastReviewed":"2026-10-03"},"summary":"A score that shows how far your IGF-1 result is from the average for people of your age and sex, in standard deviations. Labs usually print it next to IGF-1.","url":"https://bloodtesttracker.com/markers/igf-1-z-score","notice":"Information, not medical advice. Ranges differ between labs, so the range on your own report is the one your result is judged against."}