Filter paper-based insulin-like growth factor assay

J AAPOS. 2015 Aug;19(4):363-5. doi: 10.1016/j.jaapos.2015.03.022. Epub 2015 Jul 30.


This study assessed validity, reliability, and feasibility of a filter paper blood spot insulin-like growth factor 1 (IGF-1) assay for retinopathy of prematurity (ROP) research. Blood samples were collected from 45 healthy children. Half of each sample was spun to obtain serum; half was applied to filter cards and stored for varying times and at different temperatures. IGF-1 assays were performed using a commercially available kit. Intraclass correlation between blood spot and serum IGF-1 values was high (0.97) for validity, and the mean differences were low for test-retest reliability. Time (up to 25 days) and temperature (4° C to 37° C) had no significant effect on sample stability. Feasibility was further assessed in a second cohort study of 74 premature infants being screened for ROP. A total of 817 filter card samples were successfully collected and transported to a central lab, where IGF-1 assays were successfully performed.

Publication types

  • Research Support, N.I.H., Extramural
  • Validation Study

MeSH terms

  • Blood Chemical Analysis / methods*
  • Blood Specimen Collection / methods
  • Child, Preschool
  • Enzyme-Linked Immunosorbent Assay
  • Feasibility Studies
  • Fingers / blood supply
  • Gestational Age
  • Healthy Volunteers
  • Humans
  • Infant
  • Infant, Premature / blood
  • Infant, Very Low Birth Weight
  • Insulin-Like Growth Factor I / metabolism*
  • Paper*
  • Reproducibility of Results
  • Retinopathy of Prematurity / blood*


  • Insulin-Like Growth Factor I