NIPT Redraw Success and Best Date Calculator

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Estimate the chance that a repeat NIPT blood draw will return a result after a low-fetal-fraction no-call, and find the first study-based redraw date.

This starts at eight days after the first draw and stays editable.

This study-based estimate applies only when the report says the chromosome risk was unchanged and a repeat sample may be considered.
Peer-Reviewed Science
Updated Dec 2025
See Methodology
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Methodology

The percentage is bilinearly interpolated from a published eight-day redraw table using maternal weight and the first sample's fetal fraction. It is not used for reports marked high risk due to low fetal fraction.