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Updated: Sep 3, 2026

Multiplex Therapeutic Drug Monitoring by Isotope-dilution HPLC-MS/MS of Antibiotics in Critical Illnesses
Published on: August 30, 2018
The guidance ratio: a measure of post-diagnostic antibiotic decision-making
Kalle Garpvall1, Alex Aljundi2, Anna Dahl3
1Astrid Lindgren Children's Hospital, Karolinska University Hospital, Stockholm, Sweden.
Background:
Scalable measures that capture post-diagnostic antibiotic decisions are lacking. We developed and validated the guidance ratio (GR), a registry-based measure of post-diagnostic antibiotic decision-making.
Methods:
We conducted a retrospective multi-centre validation study of the GR and discontinuation ratio (DR), two registry-based indicators of post-diagnostic antibiotic decision-making in paediatric febrile urinary tract infection. Prescribing outcomes were classified using rule-based algorithms and compared with manually classified outcomes from medical record review. Indicator performance was evaluated against medical record data used as the reference standard.
Results:
Among 909 episodes, the GR identified guided treatment with a sensitivity of 0.78 and specificity of 1.00. Although registry-based estimates underestimated absolute values, they closely tracked temporal prescribing patterns. Calibration substantially improved agreement with manually classified outcomes.
Conclusions:
The GR captured clinically meaningful prescribing patterns and may support scalable monitoring of post-diagnostic antibiotic decision-making in stewardship programmes.
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