Beyond Acquisition: Quantifying the Annual Carrying Cost of Long-Term Biospecimen Storage

Background: Long-term biospecimen preservation requires sustained institutional investment in storage equipment, energy or cryogen, monitoring, maintenance, and inventory management. Although biobank economics and biospecimen utilization have been examined independently, the recurring direct cost associated with maintaining existing inventories in relation to storage capacity and research utilization remains less well characterized. We introduce Annual Carrying Cost (ACC) as an operational metric for quantifying this continuing institutional investment. Methods: A retrospective observational analysis was conducted within a large academic biobank using long-term storage infrastructure and retrieval data from 2023-2025. ACC incorporated annualized equipment and monitoring-probe costs, energy and cryogen consumption, maintenance and repair, environmental monitoring, and inventory management. Storage capacity was characterized according to inventory-bearing, online contingency, and offline/staged reserve capacity. ACC was normalized to available and occupied vial positions and evaluated in relation to annual research-directed vial-equivalent retrievals. Results: Sixteen storage units provided 832,120 vial positions, of which 272,476 were occupied (32.7%). Eight inventory-bearing units were 56.1% occupied, while 41.6% of total capacity was intentionally maintained as online contingency or offline/staged reserve infrastructure. Estimated ACC was $131,252 annually, comprising annualized equipment and monitoring probes (40.5%), energy and cryogen (30.8%), environmental monitoring (14.4%), maintenance and repair (8.4%), and inventory management (6.0%). ACC corresponded to $0.16 per available vial position and $0.48 per occupied vial position annually. Research-directed retrieval volume varied more than 13-fold across the study period, from 217,348 vial equivalents in 2023 to 16,414 in 2025, resulting in retrieval-normalized ACC ranging from $0.60 to $8.00 per vial-equivalent retrieved. Conclusions: Long-term biospecimen retention creates a measurable recurring institutional obligation that persists despite variation in annual research utilization. ACC provides a practical framework for characterizing this investment and distinguishing routinely occupied storage from infrastructure maintained for resilience and future capacity. When considered alongside scientific value, utilization, uniqueness, and anticipated future demand, ACC may support more informed capacity planning, lifecycle management, resource allocation, and sustainable long-term biospecimen stewardship.