What laboratory tests should be collected in a 15-year-old female with obesity and suspected Polycystic Ovary Syndrome (PCOS)?

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From the Guidelines

For a 15-year-old female with obesity and suspected PCOS, I recommend collecting comprehensive laboratory tests including fasting glucose, hemoglobin A1C, lipid panel, liver function tests, thyroid function tests (TSH, free T4), complete blood count, and hormonal studies including total and free testosterone, DHEAS, androstenedione, 17-hydroxyprogesterone, prolactin, FSH, and LH, with total testosterone (TT) and free testosterone (FT) as the first-line laboratory tests to assess biochemical hyperandrogenism, as per the most recent guidelines 1.

Key Laboratory Tests

  • Fasting glucose and hemoglobin A1C to assess for insulin resistance and glucose metabolism
  • Lipid panel and liver function tests to evaluate for metabolic complications
  • Thyroid function tests (TSH, free T4) to rule out thyroid disorders
  • Complete blood count to assess for any hematological abnormalities
  • Hormonal studies including:
    • Total and free testosterone to assess for hyperandrogenism
    • DHEAS and androstenedione to evaluate for adrenal and ovarian function
    • 17-hydroxyprogesterone to rule out congenital adrenal hyperplasia
    • Prolactin to rule out hyperprolactinemia
    • FSH and LH to evaluate for pituitary-ovarian axis function

Additional Tests

  • 2-hour oral glucose tolerance test to assess for insulin resistance
  • Vitamin D levels to evaluate for any deficiencies

Rationale

The recommended laboratory tests are based on the most recent guidelines 1, which suggest using TT and FT as the first-line laboratory tests to assess biochemical hyperandrogenism in the diagnosis of PCOS. These tests help confirm PCOS diagnosis, rule out other endocrine disorders, and evaluate for metabolic complications commonly associated with PCOS. Early identification of insulin resistance and metabolic abnormalities is crucial in adolescents with obesity, as these can worsen over time and lead to type 2 diabetes and cardiovascular disease if not addressed promptly. The hormonal panel helps distinguish PCOS from other conditions like congenital adrenal hyperplasia, Cushing's syndrome, or androgen-secreting tumors.

From the Research

Laboratory Tests for PCOS Diagnosis

To diagnose Polycystic Ovary Syndrome (PCOS) in a 15-year-old female who is obese, the following laboratory tests should be collected:

  • Fasting glucose and insulin levels to assess insulin resistance 2, 3
  • Lipid profile to evaluate the risk of cardiovascular disease 2, 3
  • Thyroid function tests to rule out hypothyroidism, which can mimic PCOS symptoms 4
  • Prolactin levels to rule out hyperprolactinemia, which can also mimic PCOS symptoms 4
  • Androgen levels, such as testosterone and androstenedione, to assess hyperandrogenism 4
  • FSH and LH levels to evaluate ovarian function and rule out other causes of amenorrhea or oligomenorrhea 4

Additional Tests

Additional tests that may be considered in obese adolescents with suspected PCOS include:

  • 2-hour oral glucose tolerance test (OGTT) to assess glucose tolerance and insulin sensitivity 2, 3
  • Liver function tests to evaluate the risk of non-alcoholic fatty liver disease (NAFLD) 2, 3
  • Sleep study to assess for sleep apnea or other sleep disorders, which are common in obese adolescents with PCOS 2, 3

Importance of Accurate Diagnosis

Accurate diagnosis of PCOS is essential for proper management and treatment, as well as to prevent long-term complications such as type 2 diabetes, cardiovascular disease, and infertility 4. A comprehensive diagnostic evaluation, including laboratory tests and physical examination, is necessary to confirm the diagnosis of PCOS and rule out other potential causes of symptoms 4, 5.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Polycystic ovary syndrome in adolescents with obesity.

Revista da Associacao Medica Brasileira (1992), 2021

Research

Current Guidelines for Diagnosing PCOS.

Diagnostics (Basel, Switzerland), 2023

Research

Assessment and management of obesity in childhood and adolescence.

Nature reviews. Gastroenterology & hepatology, 2011

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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