False positive pregnancy tests in systemic lupus erythematosus

Area of Science:

• Reproductive immunology
• Autoimmune diseases
• Clinical chemistry

Background:

• Systemic lupus erythematosus (SLE) is an autoimmune condition affecting multiple organ systems.
• Pregnancy tests detect human chorionic gonadotropin (hCG), a hormone primarily produced during pregnancy.
• Atypical or false positive results in diagnostic tests can lead to misdiagnosis and inappropriate management.

Purpose of the Study:

• To investigate the occurrence and potential causes of false positive 'atypical ring' pregnancy tests in patients with systemic lupus erythematosus.
• To correlate these abnormal test results with clinical findings and hCG levels in SLE patients.

Main Methods:

• Retrospective analysis of 14 patients with systemic lupus erythematosus who presented with 'atypical ring' positive pregnancy tests.
• Review of patient records for clinical symptoms, including proteinuria and menstrual status (menopause, amenorrhea).
• Measurement of serum human chorionic gonadotropin (hCG) levels in affected patients.

Main Results:

• Fourteen SLE patients exhibited false positive 'atypical ring' pregnancy tests.
• Abnormal test results were associated with heavy proteinuria in 8 patients and menopause or drug-induced amenorrhea in 4 patients.
• Only one patient had a true pregnancy; 13 patients had normal serum hCG levels, indicating non-pregnant states.

Conclusions:

• False positive 'atypical ring' pregnancy tests can occur in systemic lupus erythematosus patients.
• These false positives may be linked to conditions like heavy proteinuria or amenorrhea in SLE, rather than pregnancy.
• Careful clinical correlation and hCG level assessment are crucial when interpreting pregnancy tests in SLE patients to avoid misdiagnosis.