24 hour urine collection sample detected no mercury, is this test reliable?

[Guest guest]

hello everyone,

I suspected that i am mercury poisoned,beacuse i am exposed to element

mercury vapor in my lab (chemistry PhD student)for a long time though

in very low concentration, . a fresh headache last for around 2 month

recently, the headache is not stable, sometime good, sometime worse,I

did a 24 hour urine test, the result is negative, my doctor told me

that mercury in my urine is zero. anyone have any idea on this? i

would appreciate any response.