Using a sample of our blood has long been the way to detect any infections that we may have. Traces of an infection will be present in our blood due to it travelling to each of our body cells so it picks up everything inside us such as any bacteria which would normally not be present.
The first thing a doctor will possibly ask you to do if you feel unwell is to attend the blood clinic so that they can take an amount of your blood for testing. They are able to request a whole host of different tests by ticking the coded boxes on your blood test form it is not unknown for them to ask for a full blood screening. The person who obtains your blood sample will know which colour coded sample bottles that need to be used and how much blood is needed for testing in each one. Once taken your samples will then be tested in the in house pathology laboratory and the results are sent back to your doctor and he will explain them in a follow up appointment.
When you attend an STD clinic in particular you will be given both a blood test and an examination, the reason for this is you have been proactive and gone to the clinic without waiting too long after having unprotected sex, and this is a good thing on your part. In your blood test there may be only a slight low level of bacteria at the time, so using a swab or a urine sample is a way to confirm infection. A physical examination by a person who is very highly trained will then be able to show any genital changes which you possibly wouldn’t have been able to notice yourself.
There are some instances when you can avoid having to have a blood test when visiting a STD clinic, but this is purely because some infections do and will show up much clearer by having a simple swab taken and providing a urine sample instead of a blood one. This does depend however on what STD virus they think you may have. Blood will need to be used to confirm the presence of Hepatitis B, HIV and Syphilis, most of the time with other STD infections any blood sample which has been used will just be a confirmation that the diagnosis using other means were correct. Blood tests do have however the disadvantage of taking much longer to reveal its results when compared with a urine or swab sample.
Medicine and treatments are constantly evolving so perhaps sometimes in the future any STD infection may be able to rely on a urine sample and a swab to test for the presence of bacteria. That would certainly be good news to those of us who are a squeamish when it comes to having to give a blood sample.