[About a case of macro-FSH analytical interference]

Area of Science:

• Endocrinology
• Reproductive Medicine
• Clinical Chemistry

Background:

• Premature ovarian failure (POF) is a concern in reproductive-aged women presenting with menstrual irregularities.
• Elevated follicle-stimulating hormone (FSH) with normal luteinizing hormone (LH) levels can suggest POF, necessitating thorough investigation.

Observation:

• An 18-year-old woman exhibited menstrual cycle disorders and elevated FSH with normal LH, initially suspected as POF.
• Initial investigations suggested analytical interference rather than true ovarian dysfunction.

Findings:

• The elevated FSH levels were ultimately attributed to a macro-FSH complex, formed by FSH bound to an autoantibody.
• Heterophilic antibodies and human anti-mouse antibodies (HAMA) were considered but ruled out as the primary cause.

Implications:

• This case underscores the critical need to consider analytical interferences, such as macro-FSH, in diagnosing endocrine disorders.
• Accurate interpretation of gonadotropin levels requires awareness of potential artifactual elevations to avoid misdiagnosis of premature ovarian failure.