Appendix A: incidence and positive predictive values
Updated 23 April 2025
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The table below shows the approximate UK incidence and positive predictive value of each condition.
The positive predictive value (PPV) is the likelihood that a baby with a screen positive result will have the condition. This varies with each condition.
| Condition | UK incidence | PPV% | Without early treatment, the condition can result in |
|---|---|---|---|
| SCD | 1 in 2,800 | 95% | severe pain, life threatening infections and anaemia (symptoms can be present even with treatment) |
| CF | 1 in 2,500 | 70% | poor weight gain, frequent chest infections and reduced life expectancy (symptoms can be present even with treatment) |
| CHT | 1 in 2,000 | 70% | permanent, serious physical problems and learning disabilities |
| PKU | 1 in 10,000 | 80 to 90% | permanent brain damage and serious learning disabilities |
| MCADD | 1 in 10,000 | 80 to 90% | serious illness, coma and possible death |
| MSUD | 1 in 150,000 | 50% | coma, permanent brain damage and possible death |
| IVA | 1 in 150,000 | 50% | coma, permanent brain damage and possible death |
| GA1 | 1 in 300,000 | 50% | coma and brain damage which affects muscle movement |
| HCU | 1 in 300,000 | 50% | learning difficulties, eye problems, osteoporosis, blood clots or strokes |