Action values for tandem mass spectrometry screening
Published 24 November 2021
Applies to England
© Crown copyright 2021
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These are the current action values for haemoglobins analysed as part of the newborn blood spot screening for sickle cell disease.
| Experiment | Action Value |
|---|---|
| Hb S/Beta T1 | >0.1 |
| Hb C/Beta T1b4 (694.42/451.27) | ABI Sciex>0.5/Waters Micromass >1.0 |
| Hb C/Beta T1b3 (347.72/350.2) | ≥ 0.08 |
| Hb DPunjab/Beta T13 | >1.0 |
| Hb E/Beta T3 | >0.2 |
| Hb OArab/Beta T13 | >0.1 |
| Gamma T5 Ratio | >2.5 |
| Gamma T2 Ratio | <0.2 i and >4.0 |
| Internal standard | - ii |
i Babies over 30 days of age whose only abnormality is a ratio <0.2 do not need to have second line testing, unless transfusion reported on blood spot card.
ii Internal standard values should be set by each laboratory but the following low and high action values should be used as a guide:
- AP4000 (AB Sciex, Warrington, UK) <200 and >3600
- AP4500 (AB Sciex, Warrington, UK) <1000 and >6000
- Zevo TQMS (Waters Micromass, Manchester, UK) <2000 and >15000
Reference: Tandem Mass Spectrometry for Sickle Cell and Thalassaemia Newborn Screening Pilot Study. Version 1.0/21 January 2015. Y Daniel, J Henthorn.