["\nAbstract\n\nAim\nHow can we convert biomarkers into reliable, validated laboratory tests? Glomerular filtration rate (GFR) estimators exist for more than a century. The first utilitarian biomarkers were endogenously produced urea and creatinine. Clinicians then developed simple tests to determine whether or not renal tubular function was maintained. Are there faster and better tests that reflect decreased renal function and increased acute kidney injury (AKI) risk?\n\n\nMethods\nWe inspect earlier, and recently propagated biomarkers. Cystatin C reflects GFR and is not confounded by muscle mass. Direct GFR and plasma volume can now be measured acutely within 3 hours. Better yet would be tests that give information before GFR decreases and prior to urea, creatinine, and cystatin C increases. Prospective tests identifying those persons likely to develop AKI would be helpful. Even more utilitarian would be a test that also suggests a therapeutic avenue.\n\n\nResults\nA number of highly provocative biomarkers have recently been proposed. Moreover the application of big data from huge electronic medical records promise new directions in identifying and dealing with AKI.\n\n\nConclusions\nPipedreams are in the pipeline; the novel findings require immediate testing, verification, and perhaps application. Future research promises to make such dreams come true.\n\n", "Acta Physiologica, Volume 231, Issue 1, January 2021. "]