Signatera FAQ | Natera

Signatera FAQs


What is Signatera and what does it test for?

Signatera is a personalized molecular test for the detection of circulating tumor DNA (ctDNA) in the blood of patients previously diagnosed with cancer. This testing can be used to detect minimal, or molecular, residual disease (MRD) following surgery, to monitor response to cancer treatment, or detect cancer recurrence following a period of remission.

How is Signatera different from current biomarker tests?

Signatera is not a traditional oncology test. It does not focus on well-characterized mutations, oncogenes or hotspots like most tests. Instead, Signatera utilizes a WES-based, tumor-informed approach to create 16 bespoke assays that target specific, and generally unique, mutations found in your patient’s tumor, but absent in their germline DNA.

Results and Reports

How accurate is Signatera?

Signatera is an extremely sensitive and specific test, due to the fact that it is customized specifically from your patient’s tumor. The specificity is >99.5%, and we are able to control for false positives that would result from the detection of natural background variants that occur in the patient’s DNA. The sensitivity is also remarkable as Signatera can detect a single ctDNA molecule from 10mL of plasma. In fact, our clinical studies have shown that over 50% of the time, Signatera will first detect the presence of ctDNA at a variant allele frequency (VAF) between 0.01-0.1%, far superior to our competitors who have a lower limit of detection equivalent to VAF between 0.1-1%.

What do the results mean?

A Signatera positive result indicates the presence of circulating tumor DNA (ctDNA) in your patient’s blood and by extension, the presence of tumor in the patient’s body. Positive results are highly correlated with inferior prognosis (e.g. reduced disease-free survival). The numerical value is associated with overall tumor burden for each patient, but only on a relative basis compared to previous Signatera results. In other words, the significance is in the trend; is the amount of ctDNA detected increasing, decreasing, stable from one time point to another. We have not proven that a certain quantity of ctDNA detected equates to a certain outcome, prognosis, tumor-burden or disease state; this likely varies from person to person. However, increases in MTM/mL for a given patient are associated with an increase in tumor burden for that patient and visa versa.

A negative result indicates that ctDNA was not detected in your patient’s blood at a given timepoint. This does not mean that the patient is in remission (absence of cancer that has been treated), rather it could mean that the tumor burden that remains is at such low levels that it is not detected in the blood. For this reason, Signatera is best utilized when ordered repetitively, so that ctDNA detection and/or ctDNA levels can be assessed in a longitudinal manner. The longer the patient remains ctDNA negative, the more likely that individual will not relapse.

Ordering & Logistics

How long does it take to get my results?

The first time the Signatera test is ordered, it will take two weeks for tumor-tissue sequencing results to become available from the date the tumor tissue is received. Then, it will take another two weeks for your personalized test design and for your physician to receive the first Signatera test result. After the test has been designed, your Signatera test results will become available to your physician one to two weeks after your blood sample is received by the Natera laboratory.

What is needed to start Signatera?

Talk to your oncologists about ordering Signatera. Your oncologists will need to complete a requisition form requesting that Signatera be performed. After that, once we have received your initial blood samples our team will work with you pathologist to obtain tissue samples. If tissue is not available, Signatera cannot be performed.

What type of samples are needed?

For initial testing we require one FFPE block with >25mm^2 of surface area (tissue block) and one H&E slide (preferred) OR 6-10 (10 microns) or 12-20 (5 microns) slides and one H&E slide (10 micron thickness). We also require two 10mL streck tubes and one 6mL EDTA tube. For subsequent testing, we require two 10mL Streck tubes only.


How much will it cost patients?

We have programs to help patients better afford our tests. Our patient assistance programs qualify patients for a highly discounted rate based on their individual financial situation. If you have questions or are in need of financial assistance, please contact our Patient Advocate Team at

Customer Experience

Where can I get my blood drawn for Signatera?

You can get your blood drawn at various locations that offer blood draw services. We also offer a mobile phlebotomy service at no additional cost to you.

Contact 650.489.9050 to request a home blood draw or go to our online tool to request a mobile draw or find a Natera approved lab location.


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