What is the best initial step in evaluating a patient with suspected infective vaginitis?

The best initial step in evaluating a patient with suspected infective vaginitis is a microscopic examination. This approach allows for the identification of various pathogens that could be responsible for the symptoms the patient is experiencing, such as bacterial vaginosis, yeast infections, or trichomoniasis. By examining the vaginal discharge under a microscope, the healthcare provider can look for characteristic findings, such as the presence of clue cells, yeast forms, or motile organisms, which can provide a definitive diagnosis.

Other methods, such as a complete blood count or pelvic ultrasound, do not provide immediate diagnostic insight specific to vaginitis. Starting antibiotics without a proper diagnosis may not be appropriate, as the underlying cause of the symptoms may be unrelated to a bacterial infection or may require a different treatment approach. Therefore, the microscopic examination is pivotal in leading to the correct diagnosis and guiding appropriate treatment for the patient.