Syphilis Tests

Why It Is Done

A syphilis infection can spread through the bloodstream to all parts of the body. If not treated, syphilis can cause severe heart disease, brain damage, spinal cord damage, blindness, and death.

A test for syphilis is done to:

• Screen for syphilis or check how well treatment is working. Screening tests help your doctor look for a certain disease or condition before any symptoms appear. This increases the chance of finding the infection when it can be cured or treated to avoid long-term problems.
  • The Centers for Disease Control and Prevention (CDC) and the U.S. Preventive Services Task Force (USPSTF) recommend that all pregnant women be screened for syphilis early in pregnancy.^{footnote 1, footnote 2}
• Confirm that a person has syphilis.

Screening for syphilis and other sexually transmitted infections is often done for people who engage in sexual behaviors that put them at risk. If you have syphilis, your sex partner or partners should be told, tested, and treated to prevent serious problems and to stop the spread of the disease.

How To Prepare

Tell your doctor if you:

• Are taking any medicines, such as antibiotics.
• Are allergic to any medicines, especially antibiotics or medicine used to numb the skin (anesthetics).
• Take a blood thinner, or if you have had bleeding problems.
• Are or might be pregnant.

If you have syphilis, do not have sex until the test results show that you are no longer infected or until you and your sex partner or partners have completed treatment and the infection has been cured. Your sex partners should be tested as well.

If you think you might have syphilis, do not have sex until testing shows that you are not infected.

Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results may mean. To help you understand the importance of this test, fill out the medical test information form (What is a PDF document?).

How It Is Done

A syphilis test may be done on a sample of blood, sore, skin, or spinal fluid, depending on which type of test is done.

Blood sample

Blood test from a finger stick

For a fingertip sample, the health professional taking the sample will:

• Clean your hand with soap and warm water or an alcohol swab.
• Massage your hand without touching the puncture site.
• Puncture the skin on the side of your middle or ring finger with a small instrument called a lancet.
• Wipe away the first drop of blood.
• Place a small tube on the puncture site and collect a small amount of blood.
• Put a gauze pad or cotton ball over the puncture site as the tube is removed.
• Put pressure on the site and then put on a bandage.

Blood test from a vein

The health professional taking a sample of your blood will:

• Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.
• Clean the needle site with alcohol.
• Put the needle into the vein. More than one needle stick may be needed.
• Attach a tube to the needle to fill it with blood.
• Remove the band from your arm when enough blood is collected.
• Put a gauze pad or cotton ball over the needle site as the needle is removed.
• Put pressure on the site and then put on a bandage.

Sore or skin sample

A sample of fluid or tissue may be taken from an open sore or from a rash that might be caused by syphilis.

• A fluid sample is obtained by gently pressing the sore.
• Skin or mucous membrane samples may be obtained by gently rubbing a cotton-tipped swab over the area.

Spinal fluid sample

A spinal tap (lumbar puncture) is done to collect a spinal fluid sample for syphilis testing.

For a lumbar puncture, a thin needle is inserted into the spinal canal in the lower back. After the needle is in place, a small amount of fluid is removed from the spinal canal. To learn more, see the topic Lumbar Puncture.

How It Feels

Blood sample

The blood sample is taken from a vein in your arm or from your fingertip. You may feel nothing at all from the needle or lancet, or you may feel a quick sting or pinch. When blood is taken from a vein, an elastic band is wrapped around your upper arm and may feel tight.

Sore or skin sample

You may feel some discomfort when fluid is collected from an open sore. But syphilis sores usually are not very tender or painful.

Spinal fluid sample

You may feel some discomfort during a lumbar puncture to collect spinal fluid. To learn more, see the topic Lumbar Puncture.

What Affects the Test

You may not be able to have the test, or the results may not be helpful, if:

• You use antibiotics before you have the test.
• You have a blood transfusion in the weeks before having the test.
• You have another condition or disease, such as lupus, liver disease, HIV infection, or a tropical bacterial infection called yaws.

What To Think About

Test results

• With treatment, a positive VDRL or RPR test result usually becomes negative. Positive FTA-ABS, MHA-TP, TPPA, or rapid immunochromatographic tests stay positive for a lifetime, even after syphilis has been cured.
• In the United States, your health professional must report to the state health department that you have syphilis.

Syphilis and HIV infection

• Sores caused by syphilis make it easier to get and spread an HIV infection.
• People with HIV who have a negative VDRL test should have a second test for syphilis if the infection is suspected.