needle stick worry!

[zidanr]

good day doctors. on 13 may i stood on a sharp object on a beach in thailand. im not sure what it was but it felt quite sharp and painful. i did not get the opportunity to inspect the object as it was very dark. the beach was near a local fishing village. when i inspected my foot about an hour later i could find no puncture wound, redness or bleeding. if it was a syringe,or needle , and possible had hiv tainted blood, what are my chances of infection. if there were no obvious signs of puncture to the skin, can i be sure there was no skin penetration. many thanks doctors.

[Edward W Hook, MD]

In general we do not recommend HIV PCR testing for diagnosis is HIV infection for several reasons.  While the PCR is likely to become positive more quickly than other antibody detection tests (i.e. usual blood tests), at the present time the blood tests are becoming more and more sensitive and detecting infection earlier and earlier so that the time difference in detection between PCR test and antibody detection tests is becoming smaller and smaller and at present is, in general only a week or two.  In addition the time course over which the PCR tests become positive is less well described than for the blood tests and, as a result, it is difficult to make a definitive statement on what a negative PCR test means at any time within a few weeks of exposure to a HIV infected or possibly infected partner.  PCR tests are also more expensive than regular antibody tests.  Finally and most importantly, the false positive rate for PCR tests (i.e. a positive result in persons who do not have HIV) is higher than for blood tests.  Each of this on this Forum have seen a number of people who were worried needlessly because of false positive tests. For all of these reasons, we rarely recommend testing for HIV diagnosis using PCR.  

[zidanr]

thank you for the prompt response doctor. at which stage would i be able to take a pcr test and have confidence in the results. i am to marry soon and i am really anxious. would a puncture have left a mark? thanks once again doctor

[Edward W Hook, MD]

Welcome to our Forum. there are many unknown factors in the situation you describe which make it impossible to realistically determine the probability of having been infected in the situation you describe. these include:

1. You do not know what it was that you felt on the beach.  There are many possibilities other than needles.
2.  If it was a needle, you do not know if it was used or how long it had been present on the beach.  Most people, even IV drug users do not have HIV and HIV does not survive for long periods of time when outside of the body.

If the injury was due to a needle and if it was contaminated, your risk for infection would be no greater than about 1%.  At this time, there is nothing that can be done.  You are far beyond the time when preventative therapy would have any benefit.  If this is something that worries you, I suggest that you have a blood test.  Combination HIV p24 antigen/HIV antibody (DUO) tests provide definitive answers at about 4 weeks following exposure while standard, HIV only blood tests provide definitive answers at 8 weeks.  In the meantime, my recommendation is not to worry.  The risk if low and there in nothing can be done in the meantime.  Take care. EWH