A higher number of laboratory measurements is associated with mortality in patients admitted to hospital, but is not part of the frailty index based on laboratory tests (FILab). This study aimed to modify the FI-Lab (mFI-Lab) by accounting for the number of laboratory measurements and compare its validity to predict institutionalization and mortality at three-month post-discharge with the clinical frailty scale (CFS) in geriatric rehabilitation inpatients. In 1819 patients (median age 83.3 [77.6–88.3], 56.6% female), a higher FI-Lab was not associated with institutionalization but a higher risk of mortality. A higher mFI-Lab was associated with lower odds of institutionalization but a higher risk of mortality. A higher CFS was associated with institutionalization and higher mortality. The Akaike information criterion value was lowest for the CFS, followed by the mFI-Lab and the FI-Lab. The CFS is better than the mFI-Lab predicting short-term adverse outcomes in geriatric rehabilitation inpatients. When using laboratory data to estimate frailty, the mFI-Lab rather than the FI-Lab should be used.

较高数量的实验室测量值与入院患者的死亡率相关，但不是基于实验室测试 (FILab) 的衰弱指数的一部分。本研究旨在通过考虑实验室测量的数量来修改 FI-Lab (mFI-Lab)，并将其预测出院后三个月的制度化和死亡率的有效性与老年康复住院患者的临床衰弱量表 (CFS) 进行比较. 在 1819 名患者（中位年龄 83.3 [77.6–88.3]，56.6% 为女性）中，较高的 FI-Lab 与收容机构无关，但与较高的死亡风险相关。较高的 mFI-Lab 与较低的制度化几率相关，但与较高的死亡率风险相关。较高的 CFS 与制度化和较高的死亡率相关。CFS 的 Akaike 信息标准值最低，其次是 mFI-Lab 和 FI-Lab。CFS 优于 mFI-Lab 预测老年康复住院患者的短期不良结果。当使用实验室数据估计衰弱时，应使用 mFI-Lab 而不是 FI-Lab。