在pH 7.0和37℃条件下，β-羟丁酸在β-羟丁酸脱氢酶（HBDH）催化下脱氢生成乙酰乙酸，同时NAD⁺被还原为NADH；在pH 8.8和37℃条件下，乙酰乙酸在HBDH催化下被还原为3-羟基丁酸酯，或脱羧生成丙酮，同时NADH被氧化为NAD⁺。NADH在340 nm处具有特征吸收峰，通过测定该波长下吸光度的变化，即可分别定量β-羟丁酸和乙酰乙酸的含量，从而计算样本中酮体的总量。
Under the conditions of pH 7.0 and 37 °C, β‑hydroxybutyrate is dehydrogenated to acetoacetate by β‑hydroxybutyrate dehydrogenase (HBDH), with concomitant reduction of NAD⁺ to NADH. Under the conditions of pH 8.8 and 37 °C, acetoacetate is reduced by HBDH to 3‑hydroxybutyrate, or decarboxylated to acetone, with concomitant oxidation of NADH to NAD⁺. NADH exhibits a characteristic absorption peak at 340 nm. By measuring the change in absorbance at this wavelength, the contents of β‑hydroxybutyrate and acetoacetate can be quantified separately, thereby allowing calculation of the total ketone body content in the sample.
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