Sexually transmitted infection screening (Family medicine): Clinical sciences

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Introduction0:00–0:41

Sexually transmitted infections, also known as STIs, are infections acquired through sexual contact. While many STIs have symptoms, some patients present asymptomatically.
For this reason, screening is important in diagnosing and treating STIs. Screening also provides an opportunity to educate patients on safe sexual practices and disease prevention.
Specific screening recommendations for STIs vary according to biological sex, pregnancy status, sexual preference, and HIV status.
For patients presenting for STI screening, first perform a focused history and physical examination. The patient might be asymptomatic, or they may report STI symptoms, such as dysuria, genital discharge, or rash.

Screening and assessment 0:41–1:57

There also might be a history of known STI exposure. If so, ask about the timing of the sexual exposure and review previous screenings or treatment results.
Physical examination may show cervical or penile discharge, or possibly genital, rectal, or pharyngeal lesions. Here’s a clinical pearl!
Patients who are high-risk for STIs include those who have multiple sex partners, engage in transactional sex, use illicit substances, or have a history of incarceration.
Here’s another clinical pearl! STI screening can be completed at a specific STI screening visit or as part of a preventative visit, like a well-patient care exam.
STI screening can also be completed without a physical exam by patient-collected swabs, and lab tests such as blood and urine tests; however, this type of screening is only appropriate for asymptomatic patients.
Okay, let’s start by talking about which infections are screened for and how that screening is completed. Chlamydia, caused by Chlamydia trachomatis, is the most frequently reported bacterial STI with the highest prevalence in patients who are under 25 years of age.

Infections1:57–6:40

Gonorrhea, caused by Neisseria gonorrhoeae, is the second most frequently reported bacterial STI. Testing for both is completed through a nucleic acid amplification test or NAAT.
If a provider obtains a sample for testing, a specimen collection swab is used to obtain the sample from the patient’s cervix or urethra.
If the patient collects their own sample, either a vaginal swab or first catch urine specimen can be used. Positive results are reported to the CDC.
On the other hand, trichomoniasis, caused by Trichomonas vaginalis, is not a reportable disease. That said, it has a higher prevalence rate than gonorrhea or chlamydia and is known to increase the risk of HIV.
Testing is done by NAAT test using a cervical or vaginal swab, or a first catch urine sample. NAAT is preferred for its increased specificity and sensitivity, but screening can also be completed via wet mount microscopy with visualization of motile trichomonads, which confirms the diagnosis.
HIV screening is typically completed by using an antigen/antibody test for HIV 1 and 2. Positive test results are reportable to the CDC.
Next, syphilis screening, which is caused by Treponema pallidum, is usually completed by a two-step process. A non-treponemal test is obtained first, either a Venereal Disease Research Laboratory, or VDRL; or Rapid Plasma Reagin, or RPR.
This is followed by a treponemal test, such as the T. pallidum passive particle agglutination, or TP-PA test.
A positive test is reportable to the CDC. Remember to test these patients for HIV too since there is a possibility of co-infection.
Now, hepatitis B screening has traditionally been done by checking for hepatitis B surface antigen or HBsAg. However, the CDC now recommends the triple panel test.
This panel is composed of HBsAg; antibody to hepatitis B surface antigen, or anti-HBs; and total antibody to hepatitis B core antigen, or total anti-HBc.
This test is recommended because there can be a window during an acute infection when the HBsAg and anti-HB are both negative.
During this window, the only test that can accurately detect an acute infection is the total anti-HBc. Positive results are reported to the CDC.
Moving on, hepatitis C screening is simple and is done by checking for serum hepatitis C antibodies. Positive results are reported to the CDC.
Now, screening for human papillomavirus, or HPV, looks for high-risk types of the human papilloma virus, and is usually co-tested along with routine cervical cancer screenings, as indicated based on age and previous screening.
Finally, herpes simplex virus screening, or HSV, is only indicated when a patient has a suspicious genital lesion. These lesions are initially painful and vesicular and are followed by ulceration.
A prodromal period of tingling or itching may precede their appearance. HSV testing is done by obtaining a swab of fluid from the ulcer, which is analyzed by polymerase chain reaction, or PCR for both HSV 1 and 2.
Keep in mind that testing is not always necessary, and the diagnosis can be made clinically. While traditionally HSV 1 was thought to only cause oral herpes or cold sores and HSV 2 only caused genital outbreaks, evidence shows that either strain of the virus can cause an outbreak in either area.
Additionally, all patients who have suspicious lesions should also have serology testing for type-specific antibodies to HSV 1 and 2.
Now, let's break down screening recommendations into patient categories, by assessing your patient’s biological sex. Keep in mind that for transgender and gender-diverse patients, you should screen for STIs according to their anatomy.

Assess Biological Sex6:40–6:58

If your patient is a biological female, assess their pregnancy and HIV status. Let’s start with non-pregnant biological females without HIV.

Biological Female6:58–7:07

Not Pregnant, HIV negative7:07–8:47

Screen these patients for chlamydia and gonorrhea for sexually active patients under 25 years old. HIV screening is recommended for patients aged 13 to 64 years of age as an opt-out modality, meaning they will be tested for HIV unless they specifically decline the screening.
Hepatitis C screening is recommended for those over the age of 18, except in settings where the hepatitis C positivity is less than 0.1 percent.
Now, human papillomavirus screening, or HPV, looks for high-risk types of the human papilloma virus, and can be co-tested along with routine cervical cancer screenings, as indicated based on age and previous screening.
Now, patients who are considered high-risk will need additional screening. Remember, high-risk patients include those who have multiple sex partners, engage in transactional sex, use illicit substances, or have a history of incarceration.
Start by screening for chlamydia and gonorrhea if your patient is 25 years of age or older. Trichomoniasis screening should be considered for those receiving care in high-prevalence settings, such as STI clinics and correctional facilities, and for asymptomatic patients at high-risk for infection.
You’ll also want to screen for syphilis and hepatitis B. Screen for HIV with patients who are less than 15 years of age or 65 and older.
Finally, HSV screening is indicated if there’s a suspicious genital lesion. Okay, now let’s move on and discuss STI screening for pregnant patients who are HIV negative.

Pregnant, HIV negative 8:47–10:27

This is a little more straightforward as it’s performed via an opt-out panel at your patient's first prenatal visit. The panel includes chlamydia and gonorrhea if they’re under 25 years old; HIV; syphilis; hepatitis B; and hepatitis C except in settings where the hepatitis C positivity is less than 0.1 percent.
Other screenings include HPV and cervical cancer screening as with non-pregnant patients. Now, here’s a clinical pearl!
If your pregnant patient tests positive for chlamydia, a test-of-cure is indicated 3 to 4 weeks after treatment and then again within 3 months.
If positive for gonorrhea, repeat testing is indicated within 3 months, or sooner if reinfection is suspected. And here’s another clinical pearl to keep in mind!
If your patient declines HIV screening at their prenatal visit, rapid HIV testing can be performed at delivery, unless the patient declines.
Okay, if your pregnant patient is at a high-risk for infection, additional screening is recommended. This includes chlamydia and gonorrhea if your patient is 25 years or older.
And don’t forget to screen for HSV if your patient has a suspicious genital lesion. Then, repeat testing for syphilis at 28 weeks and at delivery; hepatitis B at delivery; and HIV in the third trimester.
Okay, let’s talk about screening of biologically female patients who are HIV-positive, regardless of pregnancy status. These patients should be screened for chlamydia, gonorrhea, trichomonas, and syphilis at least annually, while hepatitis B and hepatitis C should be screened at the time of HIV diagnosis.

HIV Positive - Regardless of Pregnancy Status10:27–11:07

Remember to perform HPV and cervical cancer screening based on the patient’s age and previous screening. Also consider HSV screening for symptomatic patients, those who request it, or those who have multiple partners.
Now that we’ve covered STI screening in biological females, let’s now discuss the screening recommendations for biological males.

Biological Male - Assess Sexual Preferences/HIV Status 11:07–11:20

Begin by assessing their sexual preferences and HIV status. First up are biological male patients without HIV who only have sex with biological women.

Sex with Biological Women, no HIV 11:20–12:27

Screen these patients at least once for HIV between the ages of 13 and 64 and at any time they request screening. Also, screen all patients over 18 at least once for hepatitis C, except in settings where the hepatitis C positivity rate is less than 0.1 percent.
Now, remember to identify if your patient is high-risk, which includes those who have multiple sex partners, engage in transactional sex, use illicit substances, or have a history of incarceration.
These patients need syphilis and hepatitis B screening, along with HIV screening if they’re between the ages of 13 and 64.
Chlamydia and gonorrhea screening, while not routinely performed in these patients, can be considered if there is known or suspected exposure.
Lastly, consider HSV testing for symptomatic patients, for those who request it, or for those who have multiple partners.
Next up are biological male patients without HIV who exclusively have sex with biological males or have sex with both biological males and females.

Sex with Biological Men, No HIV12:27–13:23

For these patients, test for chlamydia and gonorrhea at least annually. While both infections can be asymptomatic, penile discharge can occur with gonorrheal infection and epididymitis can occur with either.
Screen for these diseases with NAAT, using a urine sample or urethral swab. Also screen patients in this group for syphillis and HIV at least annually; and for hepatitis B along with hepatitis C, except in settings where the hepatitis C positivity rate is less than 0.1%.
Again, you can consider HSV testing for symptomatic patients, those who request it, or those who have multiple partners.
Finally, let’s talk about biological male patients who are HIV positive, regardless of their sexual preference. In these patients, test for chlamydia, gonorrhea, and syphilis at their first HIV evaluations, and then least annually.

HIV Positive - Regardless of Sexual Preference13:23–13:52

You should also test for hepatitis B and C annually. Again, you can consider HSV testing for symptomatic patients, those who request it, or those who have multiple partners.
Alright, as a quick recap…Screening for STIs helps to diagnose and treat diseases acquired through sexual contact. STI screening also provides an opportunity to educate patients on safe sexual practices to help prevent these infections.

Review13:52–14:28

Comprehensive screening for STIs includes testing for gonorrhea, HIV, hepatitis C, hepatitis B, HPV, trichomonas, syphilis, and HSV.
Specific screening regimens vary according to biological sex, pregnancy status, sexual preference,
Sexually transmitted infection screening (Family medicine) | Osmosis