OBJECTIVE: To describe a case of falsely elevated serum antimüllerian hormone (AMH) level in an infertile 37-year-old woman with rheumatoid arthritis. DESIGN: Case report. SETTING: Lille University IVF center. PATIENT(S): A 37-year-old woman with rheumatoid arthritis demonstrating a high serum AMH level (74.5 ng/mL) and a low antral follicle count. INTERVENTION(S): Assay with a Heterophilic Blocking Tube (HBT) to avoid heterophilic interference. MAIN OUTCOME MEASURE(S): Serum AMH level, ultrasound antral follicle count, hormonal assays on the 4th day of a spontaneous cycle. RESULT(S): The results of the infertility workup were as follows: serum AMH: 74.5 ng/mL (15-fold the upper limit of normal) (immunoassay: Immunotech); LH: 3.2 IU/L; FSH: 4.5 IU/L; E2: 27 pg/mL; PRL: 10 ng/mL. The antral follicle count (follicles from 2 to 9 mm) at ultrasound was 7 for both ovaries. Because there were discrepancies between the serum AMH level and the results of the infertility workup using the bioassays, we suspected a case of falsely elevated AMH level due to heterophilic interference. An HBT tube revealed a serum AMH level of 0.63 ng/mL. CONCLUSION(S): This case illustrates, for the first time, the possibility of a falsely high serum AMH level due to heterophilic interference.
OBJECTIVE: To describe a case of falsely elevated serum antimüllerian hormone (AMH) level in an infertile 37-year-old woman with rheumatoid arthritis. DESIGN: Case report. SETTING: Lille University IVF center. PATIENT(S): A 37-year-old woman with rheumatoid arthritis demonstrating a high serum AMH level (74.5 ng/mL) and a low antral follicle count. INTERVENTION(S): Assay with a Heterophilic Blocking Tube (HBT) to avoid heterophilic interference. MAIN OUTCOME MEASURE(S): Serum AMH level, ultrasound antral follicle count, hormonal assays on the 4th day of a spontaneous cycle. RESULT(S): The results of the infertility workup were as follows: serum AMH: 74.5 ng/mL (15-fold the upper limit of normal) (immunoassay: Immunotech); LH: 3.2 IU/L; FSH: 4.5 IU/L; E2: 27 pg/mL; PRL: 10 ng/mL. The antral follicle count (follicles from 2 to 9 mm) at ultrasound was 7 for both ovaries. Because there were discrepancies between the serum AMH level and the results of the infertility workup using the bioassays, we suspected a case of falsely elevated AMH level due to heterophilic interference. An HBT tube revealed a serum AMH level of 0.63 ng/mL. CONCLUSION(S): This case illustrates, for the first time, the possibility of a falsely high serum AMH level due to heterophilic interference.