Serum beta-hydroxybutyrate

Method

Serum, plasma or capillary whole-blood beta-hydroxybutyrate concentration by enzymatic assay or point-of-care ketone meter. Time since the last dose and fasting state are recorded on the edge; the excursion after medium-chain triglyceride or ketone-ester dosing peaks within 60 to 120 minutes and a fasted trough measures something else entirely.

The method is part of the endpoint identity. Studies measuring the same quantity by a different method are held as separate endpoints.

Notes

Primarily a pharmacodynamic exposure marker for ketogenic and medium-chain-triglyceride interventions, so a rise shows that the compound did what it does, not that the patient benefited; edges resting only on this are exposure claims. The near-miss is CAT:outcome/fasting-blood-glucose, drawn from the same sample in the same panel: both are circulating fuel substrates, but this improves by RISING in these trials while glucose improves by FALLING. Distinct also from total ketone bodies and from urinary acetoacetate dipstick readings, which track a different ketone and lag blood levels by hours.