2: Diagnosis of STIs

Question 1

Diagnosis is made by microscopic visualization of organism in vaginal discharge. Point-of-care tests typically have higher sensitivity and specificity.

Answer 1

Trichomoniasis

Question 2

Diagnosis by NAATs or culture. NAATs testing not formally approved for rectum or pharynx testing.

Answer 2

Gonorrhea

Question 3

Vaginal cx or antigen testing or mobile/motile trichomonads identified on saline wet mount; Vaginal pH >5.

Answer 3

Trichomoniasis

Question 4

Culture is a sensitive and highly specific method of diagnosis, but is no longer routinely performed because of the availability of nucleic acid amplification tests (NAATs).

Answer 4

Trichomoniasis

Question 5

Can use first-catch urine or vaginal swabbings. Use NAATs, cell culture, direct immunofluorescence, enzyme immunoassay (EIA), and nucleic acid hybridization tests.

Answer 5

Chlamydia

Question 6

Dark-field examination (bacteria present on sore) and direct fluorescent antibody.

Answer 6

Syphilis (early)

Question 8

Serologic test for antibodies. Confirm with serologic test for RNA presence.

Answer 8

Hep C

Question 9

H. ducreyi bacteria on culture definitive.

Answer 9

Chancroid

Question 10

Diagnosis by NAATs preferred.

Answer 10

Chlamydia

Question 11

Diagnosis is by physical exam and biopsy can be performed on cervical lesions if diagnosis is uncertain (esp if cancer suspected).

Answer 11

HPV

Question 12

Painful ulcer w unilateral bubo. Darkfield microscopy eliminates syphilis. Serologic tests for syphilis and HIV.

Answer 12

Chancroid

Question 13

Diagnosis based on findings of pelvic organ tenderness and signs of lower genital tract infection, including mucopurulent cervicitis and cervical friability. No single lab test is available.

Answer 13

PID

Question 14

Isolation in cell culture or by polymerase chain reaction (PCR) is the preferred test.

Answer 14

Herpes

Question 15

Serology results during latency and late infection stages.

Answer 15

Syphilis (this is confirmatory)

Question 16

Initial screening is conducted with standard enzyme-linked immunosorbent assay (ELISA) or enzyme immunoassay (EIA) tests. Rapid tests are also available and yield results in minutes.

Answer 16

HIV

Question 17

Confirmatory test is Western blot (WB) or indirect immunofluorescense assay (IFA).

Answer 17

HIV

Question 18

Viral culture is less sensitive than PCS, but may work during vesicular stage of infection.

Answer 18

Herpes

Question 19

Staining shows the cellular bodies.

Answer 19

Molluscum

Question 20

Genital ulcers that are negative for syphilis and HSV.

Answer 20

Chancroid

Question 21

Serologic type-specific glycoprotein G (IgG)–based assays. Not recommended in the general public. Used for false negatives and for asymptomatic partners of infected women.

Answer 21

Herpes

Question 22

Serologic markers such as surface antigens and antibodies, as well as immunoglobulins.

Answer 22

Hep B

Question 23

Discharge on exam. Negative gonorrhea test. WBC on gm stain of discharge. >2 WBCs per oil immersion on intraurethral smear. Positive leukocyte esterase test on first void urine. Microscopic exam of sediment from spun first void urine.

Answer 23

Nongonococcal Urethritis (NGU)

Question 24

DNA testing with pap smear.

Answer 24

HPV (21+ age only)

Question 25

Cerebrospinal fluid and reactive serologic tests (CS-VDRL and CSF FTA-ABS).

Answer 25

Neurosyphilis

Question 26

Organism can only be identified by culture on a special medium that is mostly out of use. Low sensitivity even using this method.

Answer 26

Chancroid

Question 27

Rule out diagnosis mainly. +Cervical motion tenderness/chandelier sign.

Answer 27

PID

Question 28

Presumptive diagnosis with nontreponemal (VDRL and RDR) and treponemal serologic (FTA-ABS and TP-PA) tests.

Answer 28

Syphilis

Question 29

Endometrial biopsy with histopathologic evidence of endometritis. Transvaginal sonography or magnetic resonance imaging techniques showing thickened, fluid-filled tubes with or without free pelvic fluid or tubo-ovarian complex, or Doppler studies suggesting pelvic infection (e.g., tubal hyperemia). Laparoscopic abnormalities.

Answer 29

PID (most specific criteria for diagnosis)

Question 30

Diagnosis is by physical exam and history. Nits are usually visible to the naked eye. Crusts or scabs may be seen in pubic area.

Answer 30

Pediculosis (Lice)