The Preterm Birth and PROM Testing segmentation by type is anchored in two dominant immunoassay formats. Elisa platforms, prized for high throughput and quantitative precision, still absorb the largest share of spending because reference labs leverage open-system instruments to batch-test PAMG-1, IGFBP-1, fFN and CRH reagents at low cost per result; reimbursement coding (CPT 83661/83662) is well-established, so the segment expands in lock-step with hospital lab consolidation. Conversely, ELLA cartridge systems—single-use, fluorescence-driven, 15-minute workflow—command a price premium justified in triage settings where obstetricians need immediate, quantitative risk stratification; volume is smaller but value is higher, and manufacturers are locking in exclusive GPO contracts that raise effective ASP 22-30 %, making ELLA the fastest-growing dollar segment despite lower test numbers.