Table 3.

The Predicted Difference Between Observed IGF-I SDS and Average IGF-I SDS and Predicted Ratio Between IGF-I and Average IGF-I Concentrations by time25

Day	Mean Difference from Average IGF-I SDS	IGF-I Concentration Ratio
0.0	−1.22	0.62
0.5	−0.12	0.96
1.0	0.39	1.14
1.5	0.60	1.22
2.0	0.67	1.25
2.5	0.68	1.25
3.0	0.62	1.23
3.5	0.46	1.17
4.0	0.21	1.07
4.5	−0.09	0.97
5.0	−0.39	0.87
5.5	−0.64	0.79
6.0	−0.85	0.73
6.5	−1.07	0.67
7.0	−1.22	0.62

Notes: These tables may be used to estimate the average IGF-I value at steady state. It is necessary to know the day/time of injection to the nearest half day and the day/time of venipuncture for IGF-I measurement to determine the number of days since the injection. The estimated average IGF-I SDS can be determined by subtracting the value listed for the number of days since injection the sample was drawn from the measured IGF-I SDS (Average IGF-I SDS=IGF-I SDS on Day X – difference between measured IGF-I SDS on Day X and average IGF-I SDS on Day X). Similarly, the estimated average IGF-I concentration can be determined by dividing the measured IGF-I concentration value by the ratio listed for the number of days since injection the sample was drawn (Average IGF-1 concentration=IGF-1 concentration on Day X ÷ IGF-I ratio on Day X). Adapted from Lin Z, Shu AD, Bach M, Miller BS, Rogol AD, Average IGF-1. Prediction for once-weekly lonapegsomatropin in children with growth hormone deficiency. J Endocr Soc. 2022;6(1):bvab168. © The Author(s) 2021. Published by Oxford University Press on behalf of the Endocrine Society.This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs licence (https://creativecommons.org/licenses/by-nc-nd/4.0/).25

Abbreviations: IGF-I, insulin-like growth factor I; SDS, standard deviation score.