Purpose: The purpose of this study was to reduce the number of items in the Modified Finnegan Neonatal Abstinence Syndrome Tool (M-FNAST) to the minimum possible while retaining or improving its validity in a short version.
Subjects: All infants with a diagnosis of neonatal abstinence syndrome (171) who were admitted to a large neonatal intensive care unit in southwest Florida between September 2010 and October 2012 comprised the sample.
Design: This was a psychometric evaluation of 33 856 M-FNAST assessments that were downloaded from the electronic medical record.
Methods: Principal axis factoring extraction with varimax rotation was performed on the M-FNAST data. Principal components extraction was used before principal factors extraction to estimate the number of factors with the scree test and factorability of the correlation matrices with Bartlett's chi-square test, and Kaiser-Meyer-Olkin Measure of Sampling Adequacy.
Results: The M-FNAST scores ranged from 0 to 29, with a mean of 3.5 (SD = 2.5). Less than 1% (21) of infants had scores of 17 or more. Nearly all (97.7%) scores fell between 0 and 9. Most subjects were full-term gestation, but 11 were preterm between 28 and 37 weeks' gestational age. The 2-factor solution explained 23.74% of the total variance and consists of 2 factors, mild/early and moderate/advanced signs. The 2-factor solution was significantly correlated with the total score on the MFNAST (r = 0.917; P < .001). Among infants who scored 8 or greater, the total score on the 2-factor solution short form FNAST was significantly correlated with the total score on the M-FNAST (r = 0.629; P < .001).