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
Calculator updated September 13, 2026
See Methodology
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Methodology

Changing any input clears the old answer. The percentage uses the published eight-day redraw table and applies only to the report types described below; the suggested date is study-based, not a proven best date for every person.

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.