Table 1.
Performance metrics for state NBS programs that include PSY in their screening strategy and responded to the survey.
| State | GA | IL | IL | KY | MO | NY | PA | TN |
|---|---|---|---|---|---|---|---|---|
| Time Period | 9/2021–6/2023 | 12/2017–10/2021 | 10/2021–9/2023 | 2/2016–6/2023 | 4/2020–5/2023 | 1/2021–6/2023 | 5/2021–5/2023 | 7/2020–5/2023 |
| # of Births | 219,399 * | 604,000 | 244,000 | 404,626 | 215,585 | 517,514 | 257,170 | 268,719 |
| # of PSY Tests (% of total screened) | 50 (0.02%) |
394 (0.07%) |
206 (0.08%) |
128 (0.03%) |
336 (0.15%) |
37 (0.01%) |
44 (0.02%) |
17 (0.01%) |
| PSY Cutoff | 2 nM | 1.08 nM | 1.5 nM | 2 nM | 2 nM | 2 nM | 1.5 nM | 1.5 nM |
| IKD | 1 ^ | 5 ^ | 0 | 2 | 1 | 0 | 1 | 1 |
| LIKD | 0 | 0 | 0 | 0 | 0 | 0 | 3 | 0 |
| LOKD | 0 | 7 ⁋ | 5 ⁋ | 0 | 1 $ | 1 ⁋ | 2 ⁋ | 3 |
| False Positive Cases | 0 | 382 | 35 | 0 | 19 # | 36 | 38 | 13 |
| Sensitivity | 100% | 100% | 100% | 100% | 100% | 100% | 100% | 100% |
| Specificity | 100% | 99.94% | 99.99% | 100% | 99.99% | 99.99% | 99.99% | 99.99% |
| FPR | 0% | 0.063% | 0.014% | 0% | 0.009% | 0.007% | 0.015% | 0.005% |
| PPV | 100% | 3.1% | 12.5% | 100% | 9.5% | 2.7% | 13.6% | 23.5% |
| Prevalence | 1:219,399 (0.0005%) |
1:50,333 (0.002%) |
1:48,800 (0.002%) |
1:202,313 (0.0005%) |
1:107793 (0.0009%) |
1:517,514 (0.0002%) |
1:42,862 (0.0023%) |
1:67,180 (0.0015%) |
|
PPV
(prevalence) |
100% | 3.1% | 12.5% | 100% | 9.5% | 2.7% | 13.6% | 23.5% |
FPR, false positive rate; PPV, positive predictive value; PSY, psychosine; * total number of live births was not provided by state and therefore calculated for the given time periods from: Hamilton BE et al. Births: Provisional data for 2019. Vital Statistics Rapid Release; no 8. Hyattsville, MD: National Center for Health Statistics. May 2020. Available from: https://www.cdc.gov/nchs/data/vsrr/vsrr-8-508.pdf, last accessed 16 January 2024; ^ parents of two IKD cases declined HSCT; ⁋ LOKD based on reduced GALC activity, moderately elevated PSY and supportive GALC genotype; $ PSY 1.8 nM but reported because of GALC activity below “failsafe” cutoff; # incl. two false positive cases caused by a laboratory error (see Discussion and Appendix A).