A disintegrin and metalloprotease protein-12 as a novel marker for the diagnosis of ectopic pregnancy

Objective: To evaluate the performance of a novel biomarker, a disintegrin and metalloprotease-12 (ADAM-12), to differentiate an ectopic pregnancy (EP) from normal intrauterine pregnancies (IUPs).

Design: Case-control study.

Setting: Three urban academic centers.

Patient(s): Women who were seen in the emergency department with pain or bleeding in the first trimester of pregnancy.

Intervention(s): Sera from women with diagnosed EP or IUP were evaluated via proteomics and an ADAM-12 dissociation-enhanced lanthanide fluoroimmunoassay.

Main outcome measure(s): Differences between groups, area under the receiver operating curve, sensitivity, and specificity.

Result(s): Via a proteomics evaluation, we found a statistically significant decrease in ADAM-12 in the sera of patients with EP, which we confirmed in a larger group of 199 patients (median IUP 18.6 ng/mL versus median EP 2.5 ng/mL with good discrimination between the groups as assessed by receiver operating characteristics [area under the curve = 0.82]). At a low cut-point, the sensitivity was 70% and specificity 84%, but, at a higher cut-point optimizing sensitivity, the ADAM-12 test demonstrated a sensitivity of 97%.

Conclusion(s): ADAM-12 is a promising marker for the diagnosis of EP in women with symptoms in the first trimester, validating the proteomics findings. Further studies in additional patient populations and in combination with other biomarkers are needed.