The guys pushing the sensitive, mass spectrometry-based estradiol tests have good intentions, but the situation is more complex than it sounds, and everyone should know a little about the tradeoffs.
A sensitive test is capable of being very accurate provided it's done perfectly. But the equipment and methods are quite complicated and finicky, leading to a relatively high rate of very large errors. For example, 30% of my sensitive results have had no relationship with reality.
The non-sensitive, standard immunoassay tests are simple and idiot-proof, highly reliable and repeatable. The problem is that their specificity is lacking—other substances can falsely elevate the readings. Most guys should find these effects are small, maybe a pretty consistent five or 10 percent elevation.
The ideal situation is to use both methods, at least initially, until a pattern is clear. After performing this "calibration", I now rely exclusively on the non-sensitive test.
