From the Guidelines
A wet mount is a laboratory technique used to examine biological specimens under a microscope, commonly used to diagnose infections like bacterial vaginosis, trichomoniasis, or yeast infections by examining vaginal secretions. This technique involves placing a small sample of material on a glass slide, adding a drop of liquid (usually water, saline, or another solution), and covering it with a coverslip, creating a thin layer of the specimen suspended in fluid that can be directly observed under a microscope 1. The sensitivity of wet mount for diagnosing trichomoniasis is between 40% and 80% 1, and it is essential to read the wet mount as soon as the pelvic examination is completed to increase the likelihood of detecting trichomonads 1.
To prepare a wet mount, you need a clean microscope slide, coverslip, dropper, the specimen, and an appropriate liquid medium, such as saline or potassium hydroxide (KOH) solution 1. The liquid prevents the specimen from drying out and maintains its natural characteristics during examination. The wet mount can be used to identify various microorganisms, including yeast, bacteria, and protozoans, such as Trichomonas vaginalis 1.
Some key points to consider when using wet mounts include:
- The technique requires immediate viewing for optimal results, especially when detecting motile organisms like Trichomonas vaginalis 1.
- The sensitivity of wet mount can be limited, and false-negative results are common, especially for trichomoniasis 1.
- Other diagnostic tests, such as culture, nucleic acid probe, or antigen-based rapid testing, may be more sensitive and specific for certain infections 1.
- The wet mount can be used in combination with other diagnostic tests, such as pH testing and KOH preparation, to increase the accuracy of diagnosis 1.
Overall, the wet mount is a valuable diagnostic tool in clinical settings, particularly for diagnosing vaginal infections, but its limitations and the need for prompt examination should be considered to ensure accurate results 1.
From the Research
Definition of Wet Mount
- A wet mount is a diagnostic technique used to examine vaginal discharge or cervical discharge under a microscope 2, 3, 4.
- It involves preparing a slide with a sample of the discharge and adding a saline solution to create a wet environment, allowing for the examination of microorganisms and other elements present in the sample.
Applications of Wet Mount
- Wet mount microscopy is used to diagnose various vaginal conditions, including bacterial vaginosis, trichomoniasis, and candidiasis 2, 3, 5.
- It is considered a point-of-care, inexpensive, and fast technique that can be mastered by office clinicians with practice 2.
- Wet mount microscopy is recommended as a basic skill in the curricula of gynecology and obstetrics residencies 2.
Performance and Interpretation of Wet Mount
- The use of phase contrast is recommended to improve the performance and reproducibility of wet mount microscopy 2.
- Sampling location, devices, and technique have an impact on the results of wet mount microscopy 2.
- Available scoring and classification scores have significant limitations, and recommendations are provided on sampling, reading, and scoring 2.
- Wet mount microscopy has an excellent performance for the diagnosis of bacterial vaginosis and variable performance for trichomoniasis and candidiasis 2.