From the Guidelines
Perimenopause is primarily diagnosed based on a woman's age, menstrual irregularities, and characteristic symptoms, with laboratory tests such as follicle-stimulating hormone (FSH) and estradiol levels used to support the clinical assessment, but not required for diagnosis. The diagnostic criteria for perimenopause include a combination of clinical evaluation and laboratory tests, with the most useful lab test being FSH, which may be elevated (>30 IU/L) in perimenopause 1. However, a single FSH test is not definitive due to hormonal fluctuations during this transitional period.
To evaluate for perimenopause, start by taking a thorough history of menstrual changes and symptoms. If lab testing is desired, measure FSH on day 2-5 of the menstrual cycle. Consider repeating the test in 2-3 months if the initial result is inconclusive. Estradiol levels can also be checked but are less reliable due to significant variability 1. Thyroid function tests (TSH, free T4) should be performed to rule out thyroid disorders that can mimic perimenopausal symptoms. It's also important to note that FSH is not a reliable marker of menopausal status in female survivors with prior chemotherapy or pelvic radiation exposure or in female survivors on tamoxifen 1.
Some key points to consider when evaluating for perimenopause include:
- A detailed menstrual history and physical examination are essential for diagnosis
- Laboratory evaluation, including FSH, estradiol, and thyroid function tests, can be used to support the clinical assessment
- A normal FSH level does not rule out perimenopause, and an elevated level doesn't definitively confirm it
- The diagnosis remains primarily clinical, and lab tests should be interpreted in the context of the patient's age, symptoms, and menstrual pattern
- Regular follow-up and reassessment are crucial as perimenopause is a dynamic process that can last several years 1.
In terms of laboratory tests, FSH is the most useful test for supporting the diagnosis of perimenopause, but it should be used in conjunction with clinical evaluation and other laboratory tests, such as estradiol and thyroid function tests. Additionally, other markers, including anti-Mullerian hormone (AMH) and inhibin, may provide additional information on ovarian status, but alone are not reliable to ensure menopausal status 1.
From the Research
Diagnostic Criteria for Perimenopause
The diagnostic criteria for perimenopause, also known as the perimenopausal transition, are primarily based on menstrual history and age. According to 2, the prior probability of perimenopause is directly related to a woman's age. The following factors can help diagnose perimenopause:
- Self-assessment of going through the transition
- Symptoms of hot flashes, night sweats, and vaginal dryness
- High follicle-stimulating hormone (FSH) levels and low inhibin B levels
Laboratory Tests for Perimenopause
Laboratory tests are not always necessary to confirm the diagnosis of perimenopause. As stated in 2, no one symptom or test is accurate enough by itself to rule in or rule out perimenopause. However, the following laboratory tests may be used:
- FSH levels: High FSH levels can indicate perimenopause 2
- Inhibin B levels: Low inhibin B levels can indicate perimenopause 2
- Estradiol levels: Low estradiol levels can indicate menopause, but not perimenopause 3
Clinical Approach to Diagnosing Perimenopause
The clinical approach to diagnosing perimenopause involves a comprehensive evaluation of the patient's symptoms, medical history, and physical examination. As recommended in 4, the annual health examination is valuable in the perimenopausal woman and should include comprehensive screening for physical and psychological problems. The importance of individualized screening and management approaches for each woman is evident, as is the need for including the woman in the management decision-making process.
Limitations of Laboratory Tests
Laboratory tests have limitations in diagnosing perimenopause. As stated in 5 and 6, the patient history and physical examination are essential in selecting relevant diagnostic testing, which leads to a timely and accurate diagnosis. Unnecessary testing can be avoided by using the patient history and physical as a basis for selecting relevant diagnostic testing.