EndocrinologyEndocrinology

TFT, LH, FSH, and Prolactin Panel

Normal Range
TSH: 0.4-4.0 mIU/L; LH/FSH: Phase dependent; PRL: <25 ng/mL
Sample Type
Serum
Fasting
Required
Unit
Multiple Units

Function

This comprehensive endocrine panel evaluates the Hypothalamic-Pituitary-Thyroid (HPT) and Hypothalamic-Pituitary-Gonadal (HPG) axes. Thyroid Function Tests (TFT) measure the metabolic regulation, while Luteinizing Hormone (LH), Follicle-Stimulating Hormone (FSH), and Prolactin (PRL) assess reproductive health and pituitary integrity. Together, they provide a snapshot of the body's primary hormonal regulatory systems.

Why it is Ordered

This panel is frequently ordered for patients presenting with symptoms of hormonal imbalance, such as unexplained weight changes, fatigue, irregular menstrual cycles, infertility, or erectile dysfunction. It is crucial for distinguishing between primary organ failure (e.g., thyroid or ovary) and secondary failure caused by pituitary or hypothalamic dysfunction. It is also used to investigate suspected pituitary tumors (prolactinomas).

Associated Conditions

  • Hypothyroidism/Hyperthyroidism: Detected through TSH and T4 levels.
  • Polycystic Ovary Syndrome (PCOS): Often characterized by an elevated LH to FSH ratio.
  • Hyperprolactinemia: Elevated Prolactin which can cause galactorrhea or infertility.
  • Menopause/Premature Ovarian Failure: Indicated by high FSH and LH levels in females.
  • Hypogonadism: Low LH/FSH paired with low sex hormones in males.

Understanding the interplay between these hormones is vital because thyroid dysfunction can sometimes cause elevations in prolactin, which in turn suppresses LH and FSH, leading to secondary reproductive issues.

Panel Components

This test is a profile comprising the following specific markers:

Why Context Matters

Endocrine tests are highly sensitive to external variables. Prolactin levels can be falsely elevated by nipple stimulation, recent exercise, stress, or even a high-protein meal. TFTs can be influenced by biotin supplements, which interfere with many immunoassay platforms. Furthermore, LH and FSH must be interpreted strictly within the context of the menstrual cycle phase; a value that is 'normal' in the follicular phase may be 'abnormal' in the mid-cycle surge.

Lab ranges are statistical averages, not biological laws. "Normal" for a 20-year-old male isn't normal for a 60-year-old female.

Clinical References

Source-of-truth databases and clinical guidelines for TFT, LH, FSH, and Prolactin Panel:

Related Indicators

DR

Medically Reviewed by Dr. Binoy Babu, MBBS

Board Certified Doctor • 10+ Years Clinical Experience

Dr. Babu is a practicing physician dedicated to empowering patients with clear, actionable medical information. He founded 2opi to bridge the gap between complex lab reports and patient understanding, ensuring everyone has access to a reliable second opinion.

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