I would not worry about 0.01 vs. <0.01. Statistically speaking, this is a very good place to be!
However, if your brain won't let this go
, I would
not rely on a 2-decimal test when trying to get more precise information. Rather, I would monitor my PSA with Labcorp's 3-decimal ultrasensitive test. With this test you would come back with a more precise result, for example 0.011, 0.009, etc. or you might even be below this test's lower limit of detection and get a result of <0.006.
Keep in mind that, based on my own results and those of others, you should expect some fluctuation at these low levels.
This may explain why you might come back 0.01 one day and <0.01 another even with the same test.
It would simply mean that your actual PSA is hovering around 0.01. You could confirm this with Labcorp's test if you have future results of, say, 0.011, 0.009, 0.010, and so on.
Every test will give you a range of values rather than a single value if you repeat the test many times on the same blood sample. For example, in one study under ideal lab conditions Labcorp's uPSA test ranged about
±0.002 when a sample with a
prepared exact concentration of 0.010 was repeated 20 times. So it's not hard to see why a 2-decimal PSA test could give you 0.01 then <0.01 when you rerun the same sample if your PSA happens to be around 0.01. Along with that, you have to take into account that even a "stable" PSA most likely fluctuates slightly over any time period for normal physiological reasons.
Djin