Signatera positive after FIVE years??

Stage 2A colorectal cancer diagnosis in April 2021 (43 y/o at the time). Resection surgery for tumor removal (in addition to full hysterectomy, appendectomy, and gall bladder removal just to be on the safe side). No lymph node involvement. No treatments recommended due to being stage 2 with no lymph nodes involved. Have been monitored by Signatera labs every 3 months for 5 years and all results have been 0.00 (praise the Lord) until this most recent one (literally one month before being at the 5 year mark) came back 0.05. All colonoscopies over the past 5 years also came back clear. I know 0.05 is very low, but what in the world?? Why all of a sudden? Anyone ever have this happen after soooo long with 0.00? False positive possibly?? Just had my latest colonoscopy last week and it was clear. Trying not to worry but as you can imagine, that’s easier said than done….especially after thinking I was about to be essentially “out of the woods” from all of this by reaching the 5 year mark.

*Further note: I had my scheduled labs drawn in January 2026. In February, ONC lab called to tell me that Signatera was requesting a redraw due to the sample not having enough cell-free DNA (whatever that means). So I went and did new labs in February. Waited and waited for results (it should only take a week or two to get results). When March rolled around and I still didn’t hear anything, I was really confused. Then in March, ONC lab called and said the exact same thing as before “Signatera is requesting a redraw due to an issue with the sample.” I said “Again??” And she said “What do you mean ‘again?’” I told her this will be the second time I’ve been called to come do my labs again. And she was like “Oh goodness…well, we just got a call from them today that they need a new sample.” So I went again in March, and this time the results came back in their normal timeframe but with this positive 0.05 result. So I don’t know whether to think there’s an issue with how the sample was processed and maybe it’s somehow a false positive or if there’s actually something to it. I’m sure they will have me test again in a few weeks or so to see if it returns to 0.00 or is still up at all. My ONC nurse called today to get me scheduled with the ONC and she said ONC said to reassure me that she has seen this before and that in some cases it returns back to 0.0 at the next lab draw.