Use of male condoms or female condoms may help prevent the spread of trichomoniasis, although careful studies have never been done that focus on how to prevent this infection. Infection with Trichomoniasis through water is unlikely because "Trichomonas vaginalis" dies in water after 45–60 minutes, in thermal water after 30 minutes to 3 hours and in d urine after 5–6 hours.

Currently there are no routine standard screening requirements for the general U.S. population receiving family planning or STI testing. The Centers for Disease Control and Prevention (CDC) recommends Trichomoniasis testing for females with vaginal discharge and can be considered for females at higher risk for infection or of HIV-positive serostatus.

The advent of new, highly specific and sensitive trichomoniasis tests present opportunities for new screening protocols for both men and women. Careful planning, discussion, and research are required to determine the cost-efficiency and most beneficial use of these new tests for the diagnosis and treatment of trichomoniasis in the U.S., which can lead to better prevention efforts.

A number of strategies have been found to improve follow-up for STI testing including email and text messaging as reminders of appointments.

The Nugent Score is now rarely used by physicians due to the time it takes to read the slides and requires the use of a trained microscopist. A score of 0-10 is generated from combining three other scores. The scores are as follows:

- 0–3 is considered negative for BV

- 4–6 is considered intermediate

- 7+ is considered indicative of BV.

At least 10–20 high power (1000× oil immersion) fields are counted and an average determined.

DNA hybridization testing with Affirm VPIII was compared to the Gram stain using the Nugent criteria. The Affirm VPIII test may be used for the rapid diagnosis of BV in symptomatic women but uses expensive proprietary equipment to read results, and does not detect other pathogens that cause BV, including Prevotella spp, Bacteroides spp, & Mobiluncus spp.

To make a diagnosis of bacterial vaginosis, a swab from inside the vagina should be obtained. These swabs should be tested for:

- A characteristic "fishy" odor on wet mount. This test, called the "whiff test", is performed by adding a small amount of potassium hydroxide to a microscopic slide containing the vaginal discharge. A characteristic fishy odor is considered a positive whiff test and is suggestive of bacterial vaginosis.

- Loss of acidity. To control bacterial growth, the vagina is normally slightly acidic with a pH of 3.8–4.2. A swab of the discharge is put onto litmus paper to check its acidity. A pH greater than 4.5 is considered alkaline and is suggestive of bacterial vaginosis.

- The presence of "clue cells" on wet mount. Similar to the whiff test, the test for clue cells is performed by placing a drop of sodium chloride solution on a slide containing vaginal discharge. If present, clue cells can be visualized under a microscope. They are so-named because they give a clue to the reason behind the discharge. These are epithelial cells that are coated with bacteria.

Two positive results in addition to the discharge itself are enough to diagnose BV. If there is no discharge, then all three criteria are needed.

Differential diagnosis for bacterial vaginosis includes the following:

- Normal vaginal discharge.

- Candidiasis (thrush, or a yeast infection).

- Trichomoniasis, an infection caused by "Trichomonas vaginalis".

- Aerobic vaginitis

The Center For Disease Control (CDC) defines STIs as "a variety of clinical syndromes and infections caused by pathogens that can be acquired and transmitted through sexual activity." But the CDC does not specifically identify BV as sexually transmitted infection.

There are three main ways to test for Trichomoniasis.

- The first is known as saline microscopy. This is the most commonly used method and requires an endocervical, vaginal, or penile swab specimen for examination under a microscope. The presence of one or multiple trichomonads constitutes a positive result. This method is cheap but has a low sensitivity (60-70%) often due to an inadequate sample, resulting in false negatives.

- The second diagnostic method is culture, which has historically been the "gold standard" in infectious disease diagnosis. Trichomonas Vaginalis culture tests are relatively cheap; however, sensitivity is still somewhat low (70-89%).

- The third method includes the nucleic acid amplification tests (NAATs) which are more sensitive. These tests are more costly than microscopy and culture, and are highly sensitive (80-90%).

Mucopurulent cervicitis (MPC) is characterized by a purulent or mucopurulent endocervical exudate visible in the endocervical canal or in an endocervical swab specimen. Some specialists also diagnose MPC on the basis of easily induced cervical bleeding. Although some specialists consider an increased number of polymorphonuclear white blood cells on endocervical Gram stain as being useful in the diagnosis of MPC, this criterion has not been standardized, has a low positive-predictive value (PPV), and is not available in some settings. MPC often is without symptoms, but some women have an abnormal vaginal discharge and vaginal bleeding (e.g., after sexual intercourse). MPC can be caused by "Chlamydia trachomatis" or "Neisseria gonorrhoeae"; however, in most cases neither organism can be isolated. MPC can persist despite repeated courses of antimicrobial therapy. Because relapse or reinfection with "C. trachomatis" or "N. gonorrhoeae" usually does not occur in persons with persistent cases of MPC, other non-microbiologic determinants (e.g., inflammation in the zone of ectopy) might be involved.

Patients who have MPC should be tested for "C. trachomatis" and for "N. gonorrhoeae" with the most sensitive and specific test available. However, MPC is not a sensitive predictor of infection with these organisms; most women who have "C. trachomatis" or "N. gonorrhoeae" do not have MPC.

Diagnosis is typically suspected based on a women's symptoms. Diagnosis is made with microscopy (mostly by vaginal wet mount) and culture of the discharge after a careful history and physical examination have been completed. The color, consistency, acidity, and other characteristics of the discharge may be predictive of the causative agent. Determining the agent is especially important because women may have more than one infection, or have symptoms that overlap those of another infection, which dictates different treatment processes to cure the infection. For example, women often self-diagnose for yeast infections but due to the 89% misdiagnosis rate, self-diagnoses of vaginal infections are highly discouraged.

Another type of vaginitis, called desquamative inflammatory vaginitis (DIV) also exists. The cause behind this type is still poorly understood. DIV corresponds to the severe forms of aerobic vaginitis. About 5 to 10% of women are affected by aerobic vaginitis.

The International Statistical Classification of Diseases and Related Health Problems codes for the several causes of vaginitis are:

Prevention of candidiasis, the most common type of vaginitis, includes using loose cotton underwear. The vaginal area should be washed with water. Perfumed soaps, shower gels, and vaginal deodorants should be avoided. Douching is not recommended. The practice upsets the normal balance of yeast in the vagina and does more harm than good.

Prevention of bacterial vaginosis includes healthy diets and behaviors as well as minimizing stress as all these factors can affect the pH balance of the vagina.

Prevention of trichomoniasis revolves around avoiding other people's wet towels and hot tubs, and safe-sex procedures, such as condom use.

Some women consume good bacteria in food with live culture, such as yogurt, sauerkraut and kimchi, or in probiotic supplements either to try to prevent candidiasis, or to reduce the likelihood of developing bacterial vaginitis following antibiotic treatment. There is no firm evidence to suggest that eating live yogurt or taking probiotic supplements will prevent candidiasis.

Studies have suggested a possible clinical role for the use of standardized oral or vaginal probiotics in the treatment of bacterial vaginosis, either in addition to or in place of the typical antibiotic regimens. However, recent articles question their efficacy in preventing recurrence compared with other means, or conclude that there is insufficient evidence for or against recommending probiotics for the treatment of bacterial vaginosis.

Specific age groups, persons who participate in risky sexual behavior, or those have certain health conditions may require screening. The CDC recommends that sexually active women under the age of 25 and those over 25 at risk should be screened for chlamydia and gonorrhea yearly. Appropriate times for screening are during regular pelvic examinations and preconception evaluations. Nucleic acid amplification tests are the recommended method of diagnosis for gonorrhea and chlamydia. This can be done on either urine in both men and women, vaginal or cervical swabs in women, or urethral swabs in men. Screening can be performed:

- to assess the presence of infection and prevent tubal infertility in women

- during the initial evaluation before infertility treatment

- to identify HIV infection

- for men who have sex with men

- for those who may have been exposed to hepatitis C

- for HCV

If symptomatic, testing is recommended. The risk of contracting Micoplasma infection can be reduced by the following:

- Using barrier methods such as condoms

- Seeking medical attention if you are experiencing symptoms suggesting a sexually transmitted infection.

- Seeking medical attention after learning that a current or former sex partner has, or might have had a sexually transmitted infection.

- Getting a STI history from your current partner and insisting they be tested and treated before intercourse.

- Avoiding vaginal activity, particularly intercourse, after the end of a pregnancy (delivery, miscarriage, or abortion) or certain gynecological procedures, to ensure that the cervix closes.

- Abstinence

Testing may be for a single infection, or consist of a number of tests for a range of STIs, including tests for syphilis, trichomonas, gonorrhea, chlamydia, herpes, hepatitis and HIV. No procedure tests for all infectious agents.

STI tests may be used for a number of reasons:

- as a diagnostic test to determine the cause of symptoms or illness

- as a screening test to detect asymptomatic or presymptomatic infections

- as a check that prospective sexual partners are free of disease before they engage in sex without safer sex precautions (for example, when starting a long term mutually monogamous sexual relationship, in fluid bonding, or for procreation).

- as a check prior to or during pregnancy, to prevent harm to the baby

- as a check after birth, to check that the baby has not caught an STI from the mother

- to prevent the use of infected donated blood or organs

- as part of the process of contact tracing from a known infected individual

- as part of mass epidemiological surveillance

Early identification and treatment results in less chance to spread disease, and for some conditions may improve the outcomes of treatment. There is often a window period after initial infection during which an STI test will be negative. During this period, the infection may be transmissible. The duration of this period varies depending on the infection and the test. Diagnosis may also be delayed by reluctance of the infected person to seek a medical professional. One report indicated that people turn to the Internet rather than to a medical professional for information on STIs to a higher degree than for other sexual problems.

In female patients, urethritis can be caused by pelvic inflammatory disease.

In males, thepenis and testicles may show signs of pain and swelling. The urethra is visually examined by spreading the urinary meatus apart with two gloved fingers, and examining the opening for redness, discharge and other abnormalities. Next, a cotton swab is inserted 1-4 cm into the urethra and rotated once. To prevent contamination, no lubricant is applied to the swab, which can result in pain or discomfort. The swab is then smeared onto a glass slide and examined under a microscope. A commonly used cut-off for the diagnosis of urethritis is 5 or more granulocytes per High Power Field, but this definition has recently been called into doubt. The physician sometimes performs a digital rectal examination to inspect the prostate gland for swelling or infection.

A urinary tract infection may cause similar symptoms.

Risk of some causes of urethritis can be lessened by avoiding unprotected sexual activity, chemicals that could irritate the urethra; this could include detergents or lotions as well as spermicides or contraceptives, and irritation caused by manual manipulation of the urethra.

Cervicitis can be caused by any of a number of infections, of which the most common are chlamydia and gonorrhea, with chlamydia accounting for approximately 40% of cases. As many half of pregnant women are asymptomatic with a gonorrhea infection of the cervix. "Trichomonas vaginalis" and herpes simplex are less common causes of cervicitis. There is a consistent association of M. genitalium infection and female reproductive tract syndromes. M. genitalium infection is significantly associated with increased risk of cervicitis.

Regular testing for sexually transmitted infections is encouraged for prevention. The risk of contracting pelvic inflammatory disease can be reduced by the following:

- Using barrier methods such as condoms; see human sexual behavior for other listings.

- Seeking medical attention if you are experiencing symptoms of PID.

- Using hormonal combined contraceptive pills also helps in reducing the chances of PID by thickening the cervical mucosal plug & hence preventing the ascent of causative organisms from the lower genital tract.

- Seeking medical attention after learning that a current or former sex partner has, or might have had a sexually transmitted infection.

- Getting a STI history from your current partner and strongly encouraging they be tested and treated before intercourse.

- Diligence in avoiding vaginal activity, particularly intercourse, after the end of a pregnancy (delivery, miscarriage, or abortion) or certain gynecological procedures, to ensure that the cervix closes.

- Reducing the number of sexual partners.

- Sexual monogamy.

- Abstinence

A number of other causes may produce similar symptoms including appendicitis, ectopic pregnancy, hemorrhagic or ruptured ovarian cysts, ovarian torsion, and endometriosis and gastroenteritis, peritonitis, and bacterial vaginosis among others.

Pelvic inflammatory disease is more likely to reoccur when there is a prior history of the infection, recent sexual contact, recent onset of menses, or an IUD (intrauterine device) in place or if the partner has a sexually transmitted infection.

Acute pelvic inflammatory disease is highly unlikely when recent intercourse has not taken place or an IUD is not being used. A sensitive serum pregnancy test is typically obtained to rule out ectopic pregnancy. Culdocentesis will differentiate hemoperitoneum (ruptured ectopic pregnancy or hemorrhagic cyst) from pelvic sepsis (salpingitis, ruptured pelvic abscess, or ruptured appendix).

Pelvic and vaginal ultrasounds are helpful in the diagnosis of PID. In the early stages of infection, the ultrasound may appear normal. As the disease progresses, nonspecific findings can include free pelvic fluid, endometrial thickening, uterine cavity distension by fluid or gas. In some instances the borders of the uterus and ovaries appear indistinct. Enlarged ovaries accompanied by increased numbers of small cysts correlates with PID.

Laparoscopy is infrequently used to diagnose pelvic inflammatory disease since it is not readily available. Moreover, it might not detect subtle inflammation of the fallopian tubes, and it fails to detect endometritis. Nevertheless, laparoscopy is conducted if the diagnosis is not certain or if the person has not responded to antibiotic therapy after 48 hours.

No single test has adequate sensitivity and specificity to diagnose pelvic inflammatory disease. A large multisite U.S. study found that cervical motion tenderness as a minimum clinical criterion increases the sensitivity of the CDC diagnostic criteria from 83 percent to 95 percent. However, even the modified 2002 CDC criteria do not identify women with subclinical disease.

The diagnosis usually is made serologically (through complement fixation) and by exclusion of other causes of inguinal lymphadenopathy or genital ulcers. Serologic testing has a sensitivity of 80% after 2 weeks. Serologic testing may not be specific for serotype (has some cross reactivity with other chlamydia species) and can suggest LGV from other forms because of their difference in dilution, 1:64 more likely to be LGV and lower than 1:16 is likely to be other chlamydia forms (emedicine).

For identification of serotypes, culture is often used. Culture is difficult. Requiring a special medium, cycloheximide-treated McCoy or HeLa cells, and yields are still only 30-50%. DFA, or direct fluorescent antibody test, PCR of likely infected areas and pus, are also sometimes used. DFA test for the L-type serovar of C trachomatis is the most sensitive and specific test, but is not readily available.

If polymerase chain reaction (PCR) tests on infected material are positive, subsequent restriction endonuclease pattern analysis of the amplified outer membrane protein A gene can be done to determine the genotype.

Recently a fast realtime PCR (TaqMan analysis) has been developed to diagnose LGV. With this method an accurate diagnosis is feasible within a day. It has been noted that one type of testing may not be thorough enough.

The number of cases of vaginal yeast infection is not entirely clear because it is not a reportable disease and it is commonly diagnosed clinically without laboratory confirmation.

Candidiasis is one of the three most common vaginal infections along with bacterial vaginosis and trichomonas. Approximately 20% of women get an infection yearly. About 75% of women have at least one infection in their lifetime.

About 5-8% of the reproductive age female population will have four or more episodes of symptomatic Candida infection per year; this condition is called recurrent vulvovaginal candidiasis (RVVC). Because vaginal and gut colonization with Candida is commonly seen in people with no recurrent symptoms, recurrent symptomatic infections are not simply due to the presence of Candida organisms. There is some support for the theory that RVVC results from an especially intense inflammatory reaction to colonization. Candida antigens can be presented to antigen presenting cells, which may trigger cytokine production and activate lymphocytes and neutrophils that then cause inflammation and edema.

Trichomonas vaginitis is an infection acquired through sex that is associated with vaginal discharge. It can be transmitted by way of the penis to the vagina, the vagina to the penis, or from vagina to vagina. The discharge in Trichomonas is typically yellowish-green in color. It sometimes is frothy and can have a foul smell. Other symptoms may include vaginal burning or itching, pain with urination, or pain with sexual intercourse. Trichomonas is diagnosed by looking at a sample of discharge under the microscope showing trichomonads moving on the slide. However, in women with trichomonas the organism is typically detected in only 60-70% of cases. Other testing, including a culture of the discharge or a PCR assay, are more likely to detect the organism. Treatment is with a one time dose of oral antibiotics, most commonly metronidazole or tindazole.

A vaginal yeast infection results from overgrowth of candida albicans, or yeast, in the vagina. This is a relatively common infection, with over 75% of women having experienced at least one yeast infection at some point in their life. Risk factors for yeast infections include recent antibiotic use, diabetes, immunosuppression, increased estrogen levels, and use of certain contraceptive devices including intrauterine devices, diaphragms, or sponges. It is not a sexually transmitted infection. Candida vaginal infections are common; an estimated 75% of women will have at least one yeast infection in their lifetime. Vaginal discharge is not always present in yeast infections, but when occurring it is typically odorless, thick, white, and clumpy. Vaginal itching is the most common symptom of candida vulvovaginitis. Women may also experience burning, soreness, irritation, pain during urination, or pain during sex. The diagnosis of Candida vulvovaginitis is made by looking at a sample taken from the vagina under the microscope that shows hyphae (yeast), or from a culture. It is important to note that the symptoms described above may be present in other vaginal infections, so microscopic diagnosis or culture is needed to confirm the diagnosis. Treatment is with intra-vaginal or oral anti-fungal medications.

Mycoplasmas have a triple-layered membrane and lack a cell wall. Commonly used antibiotics are generally ineffective because their efficacy is due to their ability to inhibit cell wall synthesis. Micoplasmas are not affected by penicillins and other antibiotics that act on the cell wall. The growth of micoplasmas in their host is inhibited by other broad-spectrum antibiotics. These broad-spectrum antibiotics inhibit the multiplication of the mycoplasma but does not kill them. Tetracyclines, macrolides, erythromycin, macrolides, ketolides, quinolones are used to treat mycoplasma infections. In addition to the penicillins, mycoplasmas are resistant to rifampicin. Mycoplasmas may be difficult to eradicate from human or animal hosts or from cell cultures by antibiotic treatment because of resistance to the antibiotic, or because it does not kill the mycoplasma cell. Mycoplasma cells are able to invade the cells of their hosts.

As with all STIs, sex partners of patients who have LGV should be examined and tested for urethral or cervical chlamydial infection. After a positive culture for chlamydia, clinical suspicion should be confirmed with testing to distinguish serotype. Antibiotic treatment should be started if they had sexual contact with the patient during the 30 days preceding onset of symptoms in the patient. Patients with a sexually transmitted disease should be tested for other STDs due to high rates of comorbid infections. Antibiotics are not without risks and prophylaxtic broad antibiotic coverage is not recommended.

To make the diagnosis of a urinary tract infection in children, a positive urinary culture is required. Contamination poses a frequent challenge depending on the method of collection used, thus a cutoff of 10 CFU/mL is used for a "clean-catch" mid stream sample, 10 CFU/mL is used for catheter-obtained specimens, and 10 CFU/mL is used for suprapubic aspirations (a sample drawn directly from the bladder with a needle). The use of "urine bags" to collect samples is discouraged by the World Health Organization due to the high rate of contamination when cultured, and catheterization is preferred in those not toilet trained. Some, such as the American Academy of Pediatrics recommends renal ultrasound and voiding cystourethrogram (watching a person's urethra and urinary bladder with real time x-rays while they urinate) in all children less than two years old who have had a urinary tract infection. However, because there is a lack of effective treatment if problems are found, others such as the National Institute for Health and Care Excellence only recommends routine imaging in those less than six months old or who have unusual findings.

In straightforward cases, a diagnosis may be made and treatment given based on symptoms alone without further laboratory confirmation. In complicated or questionable cases, it may be useful to confirm the diagnosis via urinalysis, looking for the presence of urinary nitrites, white blood cells (leukocytes), or leukocyte esterase. Another test, urine microscopy, looks for the presence of red blood cells, white blood cells, or bacteria. Urine culture is deemed positive if it shows a bacterial colony count of greater than or equal to 10 colony-forming units per mL of a typical urinary tract organism. Antibiotic sensitivity can also be tested with these cultures, making them useful in the selection of antibiotic treatment. However, women with negative cultures may still improve with antibiotic treatment. As symptoms can be vague and without reliable tests for urinary tract infections, diagnosis can be difficult in the elderly.

Leukorrhea may be caused by sexually transmitted diseases; therefore, treating the STD will help treat the leukorrhea.

Treatment may include antibiotics, such as metronidazole. Other antibiotics common for the treatment of STDs include clindamycin or trinidazole.