CaloMax HS Sets the Benchmark for Integrated Stable Isotope Tracing

The only indirect calorimetry system with ¹³CO₂ sensing built in – not bolted on. Pioneered by TSE Systems.

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CaloMax HS is our latest innovation — a complete re-engineering of rodent indirect calorimetry from the inside out. Built on a flexible modular architecture, it integrates all critical components into a compact, intelligent system designed for long-term stability, precision, and effortless operation. The most accurate and reliable respirometry system measures the animal’s Oxygen consumption and Carbon Dioxide production to calculate key metabolic parameters, including the Respiratory Exchange Ratio and Energy Expenditure.

Integrated ¹³CO₂ Calorimetry: From Stable Isotope Insight to Reproducible Metabolic Workflows

Stable isotope tracing with ¹³CO₂ has become essential for resolving substrate utilization in vivo, distinguishing which fuels are being oxidized, tracing microbiota-derived metabolites, and quantifying exogenous versus endogenous energy metabolism continuously and non-invasively in freely moving animals. What separates reliable results from uncertain ones is not sensor sensitivity alone. It is how the entire measurement system is designed, integrated, and operated.

TSE Systems pioneered the integration of stable isotope sensing directly into indirect calorimetry — not as an add-on, but as a core architectural decision. In CaloMax HS, O₂, CO₂, and ¹³CO₂ share the same sensor module, the same sampling path, a synchronized clock, and a single unified data stream.

Architecture shapes more than measurement precision. In multi-user core facilities and long longitudinal studies, every manual step is a potential source of variability, and every added device is an added point of failure. CaloMax HS eliminates this complexity entirely — delivering reproducibility, operational robustness, and confidence in your data, from the first user to the last study.

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Infographic comparing 13CO2 stable isotope tracing system architectures: TSE Systems PhenoMaster is the best solution for stable isotope tracing with its integrated platform (4-step workflow: mouse cage, single sensor module measuring O2, CO2 and 13CO2 simultaneously, TSE Analytics software, publication-ready results) versus standalone add-on approaches used by competitors such as Sable Systems Promethion and Columbus Instruments CLAMS (5-step workflow requiring separate O2/CO2 analyzer, standalone 13CO2 analyzer, additional air pump, extra sample line, and manual data merge and alignment). PhenoMaster indirect calorimetry CaloMax HS eliminates external pumps, hardware modifications, and manual synchronization — delivering one synchronized data stream from a single integrated gas sensor module. TSE Systems pioneered 13CO2 integration into indirect calorimetry in 2018.

What Integration Delivers

One Multi-Sensor Board. Zero Compromise.
O₂, CO₂, and ¹³CO₂ are acquired from the same integrated unit, with identical sampling conditions, identical timing, and a unified calibration baseline. There is no inter-device drift to correct for and no timing offset to account for.

Turnkey from Day One.
¹³CO₂ tracing is available alongside all standard metabolic phenotyping endpoints: energy expenditure, respiratory exchange ratio, food and water intake, and locomotor activity. No separate installation procedure, no secondary sample line to manage.

Reproducibility by Design.
Integrated operation removes user-dependent variables from the isotope measurement chain. The system behaves the same across users, across cages, and across studies — because there is no separate chain to configure.

CaloMax HS: The Only True Turnkey Platform for ¹³C Tracing CaloMax HS remains the only system commercially available that offers stable isotope tracing fully integrated within an indirect calorimetry platform - not as an add-on, not as an upgrade kit, but as a core native capability of the system from the moment of installation.

CaloMax HS: The Only True Turnkey Platform for ¹³C Tracing

CaloMax HS remains the only system commercially available that offers stable isotope tracing fully integrated within an indirect calorimetry platform – not as an add-on, not as an upgrade kit, but as a core native capability of the system from the moment of installation.

Validated in peer-reviewed research across substrate oxidation, dietary intervention, and gut microbiome-host metabolism studies in rodents. A growing body of publications demonstrates its application across metabolic phenotyping research – with new research areas continuously emerging.

Your focus belongs on the biology. Ours is on making sure nothing gets in the way.

Key Features

Fully integrated isotope sensing

Stable isotope measurements are acquired within the same system as indirect calorimetry, eliminating the need for external analyzers or manual coordination.

Reduced workflow complexity

Simplified setup reduces the number of manual steps required before and during experiments.

Improved data consistency

Synchronized gas analysis supports reliable interpretation of tracer kinetics across cages and time points.

Minimized user-dependent variability

Integrated operation helps ensure reproducibility across users and laboratories.

Stable experimental conditions

Controlled airflow and reduced external disturbances support physiological measurements with minimal perturbation.

Streamlined training and operation

Turnkey design enables efficient onboarding and routine use in multi-user environments.

Publications

Jung, S., Bae, H., Song, W.-S., Chun, Y., Le, J., Alam, Y., Verlande, A., Chun, S. K., Kim, J., Kelly, M. E., Lopez, M. L., Park, S. H., Onofre, D., Baek, J., Jang, K.-H., Rubtsova, V. I., Anica, A., Masri, S., Lee, G., & Jang, C. (2025). Dietary fibre-adapted gut microbiome clears dietary fructose and reverses hepatic steatosis. Nature Metabolism, 7(9), 1801–1818. https://doi.org/10.1038/s42255-025-01356-0

Verlande, A., Chun, S. K., Song, W. A., Oettler, D., Knot, H. J., & Masri, S. (2022). Frontiers in Physiology, 13.

Fernández-Calleja, J. M. S., Bouwman, L. M. S., Swarts, H. J. M., Oosting, A., Keijer, J., & van Schothorst, E. M. (2019). Scientific Reports, 9(1), Article 1.