How do I interpret S/CO values?
No, you should not be alarmed, because the cut off values are a measure of the controls used for your test, and have nothing to do with your sample. Every time a batch of HIV tests are done, extra specimens are added that are calibrated negatives and positives, their specific values are known. Minor variations in the test can result in very small changes in end results of the test, patient values of 0.37 vs 0.44 is an example of those variations. These known controls are used to calculate the cut off for the day, the values that determine if a specimen is positive or negative. Anything close to this cut off is considered borderline, and the patient sample is tested again. There is no such thing as a zero score, that’s not how the test works. But your specimen’s value was 37% of the cutoff, which is considered a total negative. It does not mean that you had a little HIV reaction, it is just a variation in the testing procedure. The fact that you got 0.37 for a value the first two times
