IGF-1 measurements can be useful when evaluating patients of gestational age who are suspected of being growth hormone-deficient or acromegalic.

• Plasma specimens may produce falsely elevated or decreased results.

• The IGF-1 reference intervals by pubertal tanner stages reflect ranges and means based on asymmetric curves. Z-Scores are calculated based on the asymmetric curves with transformed data. Patient gender and date of birth must be provided in order to calculate a Z-Score.
  • Z-Scores will not be calculated for patients younger than 3 years old or above 18 years old.

Gold serum separator (SST) tube

1. Allow sample to clot for a minimum of 30 minutes
2. Spin and seperate within 45 minutes of collection
3. Transfer serum to a Screw-cap polypropylene frozen transport vial/tube - 4mL (LabCorp) labelled as serum
4. Freeze

Screw-cap polypropylene frozen transport vial/tube - 4mL (LabCorp)

Red serum vial/tube - 5 mL

Frozen (preferred) - 2 years

Refrigerated- 2 days

Ambient- 2 days

Serum is the only acceptable sample type

Blocking radioimmunoassy (RIA) after acid:alcohol extraction

ng/mL