From the Guidelines
A CT/NG volume of 40 on a urine screen for gonorrhea and chlamydia indicates an adequate sample volume for testing, as the minimum required volume is typically 10-20 mL, but 40-60 mL is optimal to allow for repeat testing if needed. The patient's sample volume is within the optimal range, which reduces the likelihood of false negative results due to insufficient bacterial DNA present in the sample for detection. This nucleic acid amplification test (NAAT) is highly sensitive and specific when performed correctly, and the provided sample volume is sufficient for accurate testing 1.
Key Considerations
- The USPSTF recommends screening for chlamydia and gonorrhea in all sexually active females aged 24 years or younger and in older women who are at increased risk for infection 1.
- The USPSTF also recommends screening for gonorrhea in all sexually active females aged 24 years or younger and in older women who are at increased risk for infection 1.
- Inadequate sample volume can lead to false negative results, but a volume of 40 is considered adequate for testing 1.
- If symptoms of a sexually transmitted infection are present, the healthcare provider might consider empiric treatment while awaiting proper test results, especially if the patient is at high risk or might not return for follow-up.
Testing and Treatment
- Chlamydia trachomatis and Neisseria gonorrhoeae infections should be diagnosed by using nucleic acid amplification tests (NAATs) 1.
- NAATs have high sensitivity and specificity and are cleared by the U.S. Food and Drug Administration for use on urogenital sites, including male and female urine, as well as clinician-collected endocervical, vaginal, and male urethral specimens 1.
- Chlamydial and gonococcal infections respond to treatment with antibiotics, and guidelines from the CDC on treatment of sexually transmitted diseases (STDs) and expedited partner therapy are available 1.
From the Research
Significance of CT/NG Volume on Urine Screen
The significance of a CT (Chlamydia Trachomatis)/NG (Neisseria Gonorrhoeae) volume of 40 on a urine screen for Gonorrhea and Chlamydia is not directly addressed in the provided studies. However, the studies discuss the detection of CT and NG using various methods, including nucleic acid amplification testing (NAAT) and polymerase chain reaction (PCR).
Detection Methods and Sensitivity
- The Xpert CT/NG assay, a rapid NAAT, has been shown to have excellent diagnostic characteristics, including high sensitivity and specificity for detecting CT and NG in urine samples 2.
- The sensitivity and specificity of conventional methods, such as direct fluorescence antibody (DFA) staining and Gram staining, are lower compared to molecular detection methods 3.
- Pooling samples from different anatomical sites, such as pharyngeal, anorectal, and urine samples, can be an effective strategy for detecting CT, NG, and other sexually transmitted infections (STIs) using multiplex PCR 4, 5.
Clinical Implications
- Presumptive treatment for CT and NG is a common practice, especially in emergency settings, but the rates of overtreatment and undertreatment vary widely across studies 6.
- The use of rapid and sensitive detection methods, such as NAAT and PCR, can help improve the accuracy of diagnosis and treatment of CT and NG infections.
- Further studies are needed to guide treatment practices and optimize detection methods for CT and NG infections.