Table 1.

List of the variables described for each biomarker for kidney disease in horses.

Type of Information	Details	Data Obtained from
Molecular information	Type of molecule Size	Other studies, no systematic literature search
Physiological information	Origin Function in the body Kidney physiology Structural or functional marker	Other studies, no systematic literature search
Analytical information	Which assays are available (type, brand, developed for which species, commercially available?) Analytical validation of assays for horses (phase I validation Samples to be used: blood or urine Equine reference ranges Extrarenal factors affecting reference ranges	Systematic literature search as specified in Materials and Method section
Clinical information	Validation data (overlap/clinical/outcome; phase II, II IV) Comparison to other biomarkers Results of individual studies Results of combined studies	Systematic literature search as specified in Materials and Method section
Author conclusions	What knowledge or development is still required for clinical use in horses? Level of evidence for or against use in horses	Discussion between authors, based on the above literature data

No statistical analyses were performed for this systematic review.