AIM: To investigate factors that influence urinary tissue factor (uTF) measurements: glomerular permeability and filtration, tubular function, haematuria, and urine bacterial growth. METHODS: uTF, protein creatinine index, glomerular filtration rate, retinol binding protein, N-acetyl-beta-D-glucosaminidase (NAG) and urinary haemoglobin (uHb) were measured in patients with hypertension, diabetes mellitus and nephrotic syndrome (n = 342), tubulo-interstitial disease (n = 50), and haematuria of uncertain cause (n = 50); measurements were also made in urine samples from healthy subjects for "simulated" haematuria (n = 6) and bacterial growth (n = 4) studies. RESULTS: There was a weak correlation of uTF with glomerular permeability and filtration (protein creatinine index and glomerular filtration rate) and with markers of tubular function (retinol binding protein and NAG). uTF concentrations were not affected by the presence of blood or bacteria in the urine sample. CONCLUSION: uTF concentrations are relatively stable. This is an important finding if the assay is to be used in clinical practice.