In diagnostics and medtech, revenue growing significantly faster than test/procedure volume is often NOT a bearish signal — the divergence reflects ASP expansion from payer coverage wins, improved collection rates, or product mix shift toward higher-reimbursement tests. The mechanism is structural: as a diagnostics company wins payer contracts and moves in-network, denial rates decline and reimbursement per test improves simultaneously. This is the inverse of the consumer-platform ARPU/DAU divergence heuristic (which signals monetization strain) or e-commerce take-rate expansion (which signals marketplace maturity). The key decomposition: split ASP growth into (a) coverage/collection rate improvement — sustainable, (b) product mix shift to higher-ASP tests — sustainable, (c) nominal pricing increases alone — less sustainable, faces payer pushback, and (d) multi-test attach per patient encounter — sustainable, functions as the diagnostic equivalent of NRR expansion. Factor (d) is systematically missed: when a platform adds tests that stack on the same blood draw (e.g., fetal antigen + basic NIPT, or PGx + CGP panel), ASP rises because more clinical value is delivered per encounter, not because of payer negotiation. This is a platform metric, not a pricing metric.
Do not apply the consumer-platform "revenue/volume divergence = monetization warning" heuristic to diagnostics companies. Instead, decompose ASP growth: (a) payer coverage expansion → structural, model it forward; (b) product mix shift → sustainable while mix is still shifting; (c) nominal price increases unsupported by mix or coverage → risk of pushback; (d) multi-test attach per encounter → structural platform NRR analog, most durable of all four. The real warning signal in diagnostics is concurrent deceleration in both volume AND ASP — that indicates market saturation or competitive displacement. Volume decelerating while ASP expands from payer wins or attach-rate growth is acceptable and expected during the coverage-expansion or platform-expansion phase of a diagnostics S-curve. When evaluating factor (d), look for products that can be added to the SAME blood draw with shared wet-lab infrastructure — these carry near-zero incremental COGS and compound both ASP and gross margin simultaneously.