What Types of STDs Cause Blood in the Urine?

Blood in the urine (hematuria) is not a classic symptom of most sexually transmitted infections, but the two bacterial STIs most likely to irritate the urethra enough to cause it are chlamydia and gonorrhea. More often, visible or microscopic blood points to a non-STI cause like a urinary tract infection or kidney stones. Any blood in the urine should be evaluated.

The short list: what's likely causing it

When someone notices pink, red, or tea-colored urine, the realistic culprits split into two groups. STI-related causes inflame the urethra (the tube that carries urine out), and the inflammation can be intense enough to leak a small amount of blood. Non-STI urinary causes are the more common explanation. These conditions feel so alike that symptoms alone won't sort them out, so a test settles it.

• STI-related: chlamydia and gonorrhea, both of which can cause urethritis (inflammation of the urethra) with burning and, sometimes, blood.
• Non-STI urinary causes: a urinary tract infection, kidney stones, and other bladder or kidney conditions.
• Blood in the urine always warrants evaluation, even if it clears up on its own.

Which STIs can cause blood in the urine

Chlamydia

Chlamydia is caused by the bacterium Chlamydia trachomatis; most US genital infections come from serovars D. K CDC. When it infects the urethra, the resulting inflammation produces burning on urination, and that irritated lining can occasionally bleed slightly. Mostly, though, chlamydia is silent. Roughly three quarters of infected women and about half of infected men have no symptoms at all, so many people never connect it to a urinary change.

In women, the more typical signs are abnormal vaginal discharge and burning when urinating; if the infection spreads upward it can cause lower abdominal or low-back pain, fever, pain during intercourse, and bleeding between periods, which sometimes gets confused with blood in the urine. When symptoms do show up, they usually appear within one to three weeks after exposure. If you're trying to time a test, see when to test after exposure so you don't test too early to detect it.

Gonorrhea

Gonorrhea is caused by Neisseria gonorrhoeae, which can infect the genitals, rectum, and throat CDC. It's the STI most associated with obvious urethral symptoms. In men, it classically causes burning on urination plus a white, yellow, or green penile discharge; less commonly, swollen and painful testicles. That heavy urethral inflammation is what can put blood in the urine.

In women, gonorrhea is usually silent. When symptoms do appear, they include painful or burning urination, increased vaginal discharge, and bleeding between periods. As with chlamydia, intermenstrual bleeding can be mistaken for urinary blood, so a sample helps locate the source.

When it's not an STI

Most of the time, blood in the urine isn't from an STI at all. A urinary tract infection (bacteria growing in the bladder or urethra) is the most common cause and produces frequency, urgency, and burning that can look just like gonococcal urethritis. Kidney stones (hard mineral deposits that scrape the urinary tract as they pass) cause sharp flank pain and visible blood. Other bladder and kidney conditions, certain medications, and even vigorous exercise can also color the urine. None of these involve a sexual exposure, but they share the same symptom.

How to tell them apart

You mostly can't tell by sight. These conditions overlap too much, and several of them, chlamydia and gonorrhea in women especially, are frequently silent, so the symptom you notice is a poor guide to the cause. A few patterns help a clinician decide what to test for first:

• Penile discharge with burning leans toward gonorrhea or chlamydia rather than a UTI.
• Severe one-sided flank pain that comes in waves points toward kidney stones.
• Fever with frequency and urgency, no discharge, no recent new partner, leans toward a UTI.
• Bleeding between periods in someone with a recent exposure raises suspicion for chlamydia or gonorrhea, but that's vaginal, not urinary, bleeding.

Because of this overlap, self-diagnosis fails here. A test is what turns a guess into an answer.

Side-by-side comparison

How it's tested

For the two STIs, a nucleic acid amplification test (NAAT) is the recommended method: it's the optimal test for genital and extragenital chlamydia CDC, 2021 and the preferred screening test for gonorrhea, with sensitivity usually above 90% and specificity around 99% CDC. In practice that's a urine sample, a self-collected swab, or a quick exam depending on what's suspected, with results usually back in a few days. You can do this free or low-cost at health departments, Planned Parenthood, and Title X clinics, here's how to get tested.

What to do next

Don't wait for the blood to come back to act. Get tested for chlamydia and gonorrhea if you've had a possible exposure, and ask your clinician to check a urinalysis to rule in or out a UTI or stones at the same visit. Both STIs are curable with antibiotics once confirmed, see our overviews of chlamydia and gonorrhea for what treatment involves and how to protect partners.

Red flags, get seen urgently

• Visible blood in the urine that fills the toilet bowl, passes clots, or keeps recurring.
• Fever and chills with back or flank pain, which can signal a kidney infection.
• Severe, escalating pain in the side or lower belly suggesting a stone.
• Inability to urinate, or swollen, painful testicles.
• Any blood in the urine if you're pregnant or have a known kidney condition.

Keep exploring on EasySTD: the best at-home STD tests, when to re-test and Chlamydia testing.