Table I.

GFR markers, drug levels in plasma among the most frequently ordered tests during the study period 2004–2006 (mean number of tests per year).

Test	n
1. Blood gases (ABL 725)	50725
2. Creatinine	3089
3. Blood cell counts	3070
4. C-reactive protein	3063
5. Activated partial thromboplastin time	2883
6. Prothrombin complex	2797
7. Bilirubin, direct method	1972
8. Alanine aminotransferase (ALT)	1972
17. Pt-GFR (CystC-calculated)	875
25. Vancomycin	182
28. Tobramycin	120
31. Digoxin	84
36. Gentamycin	56

Pt-GFR, Patient-Glomerular filtration rate.