It’s common in labs to see a tech walking from bench to bench with a test strip or testing device asking colleagues, “Do you see a line?” Visual reactions have chafed techs for generations.
I’ve heard two approaches:
- If you can see a line, it’s there and doesn’t matter. The doctor will repeat it if he doesn’t believe the result.
- If you have to work that hard to see a line, it isn’t there and doesn’t matter. The doctor will repeat if he doesn’t believe the result.
I agree with both to a degree, although I tend to say the latter. It’s easy enough to imagine something that isn’t there, and we’ve all done it. I’ve found it helps to move under a different kind of light. Laboratory fluorescents can be too garish for some reactions. In both cases the physician interprets the results and will certainly repeat or test an alternate method if it doesn’t fit the clinical picture.
Some of this ambivalence (“I can call this mono either way... how many reactive lymphocytes are on the smear?”) could be age related. As we age, our color vision decreases, partly due to the yellowing of our lens that may make blue colors harder to distinguish. Other causes include diabetes and certain medications e.g. blood pressure meds. I've no idea how much, but if experience in other areas is any gauge, my color vision isn’t going to get better, that’s for certain.
How do we communicate our uncertainty?
Weakly reactive pregnancy tests can be reported with a comment that recommends the physician repeat the test on a fresh morning void in 48 hours. This makes sense, since the hCG should be significantly increased by then, giving a stronger, less equivocal reaction.
Should similar “test again” recommendations be added to other weak or uncertain visual reactions?
NEXT: What-If Questions