Meaning of sensitivity of hiv test kit

[me]

Dear all,

good day.

can i ask a qn abt the sensitivity of a test kit?

I understand that the sensitivity of a test kit reflects how well it is able to detect the presence of hiv in a blood sample. The qn i am abt to ask is that, if a test kit states 99.9 % sensitivity, does that imply that out of 1000 positive test samples, it would be able to detect 999 of them.

Now if we say that these 1000 people are 1 yr post infection (i wan to rule out the window period of 3 mths plus the 1 or 2 cases in history of delayed seroconversion of up to 1 yr), does that mean that the test kit would still be able to detect only 999 of them, leaving the 1 lone case undetected?

Tks for your replies and best rgds.

[AIDS2HIV]

no...it doesnt mean 1 goes undetected...

1/10th of a percent, may get an indeterminate result, which will trigger them to retest you....so, even YOU will fall into the accurate safe zone of the test*

and the stories of long seroconversion are just that actually....taken from the past back when doctors/researchers, had no choice but to believe what people was telling them. Now a days, that isnt true, as technological advancements in medical field, proves otherwise.

Please, seek the proper care for your issues, Fear and anxiety disorders left untreated can and will fester into something beyond your control, treat it before you lose touch with reality. Good Luck & God Bless*

[Ann]

me,

Hiv tests do NOT detect the presence of hiv in the blood, they test for the presence of hiv ANTIBODIES in the blood.

Please read through the Welcome Thread and click on the links for further information.

If you have engaged in unprotected anal or vaginal intercourse, a test at 12-13 weeks will conclusively inform you of your true hiv status.

Ann

[me]

Tks ann and AIDS2HIV.

sorry abt the mistake, shd be detecting antibodies instead of hiv.

sorry to probe further. given a test kit with 99.9% specificity, and the same sample size of 1000 positive subjects, it would mean that there is always 1 who will test negative / indeterminate on the test kit, assuming that testing is done post all of their window period?

sorry about this qn, as i was juz wondering why do they put 99.9% specificity? i mean, isn't it true that regardless of what sensitivity/specificity of a test kit, as long as e subject is tested beyond the window period of 3 mths and if he/she is hiv positive, it would be shown on e test kit itself? He/she can't be the 1 out of the 1000 rite?

once again, many tks.

[harveynoble]

I think the reason they say 99.9% is that there is a chance of a false positive result. There would not be a false negative. So the inaccuracy of the test is in your favour. If the test is negative then you are negative. I think that is what they say at miraTes. I have read the leaflet my Dr gave me and it is pretty clear that the only inaccurate result will be a false postive.