What is the OVA1 test and how is it used in evaluating ovarian or adnexal masses?

What is OVA1?

OVA1 is a multivariate index assay that measures five serum biomarkers (CA-125, transthyretin, apolipoprotein A1, transferrin, and beta-2 microglobulin) to assess the risk of malignancy in women with an adnexal mass prior to surgery, but it should NOT be used as a screening tool for ovarian cancer. 1

Purpose and Clinical Context

• OVA1 was developed to help determine which patients with a pelvic mass should be referred to a gynecologic oncologist for surgery 1
• The test provides a composite risk score but does not report individual biomarker levels, requiring separate CA-125 testing if that specific value is needed 2
• It is FDA-approved specifically for preoperative assessment of adnexal masses, not for cancer screening 1

Current Guideline Recommendations

The NCCN panel does NOT recommend routine use of OVA1 for determining the status of an undiagnosed pelvic mass due to concerns about increased cost without substantial benefit and high false-positive rates. 2

Preferred Alternative Approach

• Guidelines recommend using ACOG/SGO criteria instead to determine whether a pelvic mass requires referral to a gynecologic oncologist 2
• For postmenopausal women, referral criteria include: elevated CA-125, nodular or fixed pelvic mass, metastatic disease or ascites, or family history of breast/ovarian cancer 2
• For premenopausal women, referral criteria include: CA-125 >200 units/mL (though some experts suggest >50 units/mL may be better), metastatic disease or ascites, or strong family history of breast/ovarian cancer 2

Test Performance Characteristics

• OVA1 demonstrates high sensitivity (94-97%) for detecting malignancy, making it effective at ruling out cancer when negative 3, 4
• However, it has lower specificity (50-55%), resulting in substantial false-positive rates that can lead to unnecessary referrals and interventions 3, 4
• The negative predictive value is excellent at 98-99%, meaning low-risk results reliably indicate benign disease 3, 4

Clinical Utility in Practice

• Among patients with low-risk OVA1 scores, 99% remained benign at 12-month follow-up 5
• Real-world data show that 56% of patients with low-risk OVA1 scores still underwent surgery, though 86% were minimally invasive procedures 6
• Only 21% of low-risk OVA1 patients were referred to gynecologic oncologists, suggesting general gynecologists may appropriately retain these patients 6

Reflex Testing Strategy

• A newer approach uses Overa (second-generation multivariate assay) as a reflex test for intermediate OVA1 scores to improve specificity 3
• This reflex protocol eliminated 58% of false-positives and improved overall specificity from 50% to 72% 3
• Sequential testing (OVA1 followed by ROMA for high-risk cases) can achieve a positive predictive value of 69% 4

Key Limitations and Caveats

• OVA1 is explicitly NOT approved for screening asymptomatic women for ovarian cancer 1, 2
• The Society of Gynecologic Oncologists (SGO) and FDA have both stated it should not be used as a screening tool 1
• The high false-positive rate can lead to unnecessary anxiety, specialist referrals, and surgical interventions in patients with benign masses 2
• Cost-effectiveness remains a concern, as the test adds expense without clear improvement over clinical criteria in many cases 2