There are various drugs and chemical substances that can have a significant influence on urine or sampling. Some only change thresholdvalues, others render the complete analysis unusable.
If the analyzer is unaware of the interfering substance, it can be relatively easy to make a false diagnosis, which can sometimes have serious consequences.
Medicines / Chemical Substances
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At a glance
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In the following table, schematically, some drugs or chemical substances that may have an influence on the urine sample are listed. The list is only an excerpt and has no claim to completeness.
| Interfering substance 7 factor | Influenced parameter |
| Amitriptyline | Urine color (green) |
| Beta-carotene | Urine color (yellow) |
| Betanin (Randen) | Urine color (red) |
| Captopril | Ketone (up), leukocytes (up), leukocytes (down) |
| Cefoxitin | leukocytes (up), urobilinogen (down), protein (up) |
| Cephalexin | Leukocytes (up) |
| Chemotherapy | Nitrite (down) |
| Quinidine | Protein (up) |
| Quinine | Urine color (yellow-brown) |
| Chlorhexidine | Protein (up) |
| Chloroquine | Protein (up) |
| Clavulanic acid | Leukocytes (up) |
| Curcumin | leukocytes (up), ketone (up), protein (up) |
| Deferoxamine | Urine color (red-brown) |
| Diurese / Diuretics | Specific weight (down), nitrite (down) |
| Gentamycin sulfate | Leukocytes (down) |
| Imipenem | Leukocytes (up), ketone (up), bilirubin (up) |
| Indometacin | Urine color (green) |
| Isoniazid | Urine color (orange) |
| Preservation – Boric Acid | Leukocytes (up) |
| Conservation – Formaldehyde | Leukocytes (up), Urobilinogen (down), Ketone (up) |
| Preservation – Formalin | Blood (down) |
| Long standing of the sample | Nitrite (down) (up), Urobilinogen (down), Bilirubin (down) |
| Levodopa | Urine color (red, black) |
| Meropenem | Leukocytes (up) |
| Methylene blue | Urine color (blue) |
| Metronidazole | Urine color (black) |
| Mitoxantrone | Urine color (green, blue) |
| Multivitamin preparations | Urine color (green, yellow) |
| N-acetylcysteine | Leukocytes (up), urobilinogen (down) |
| Sodium azide | Leukocytes (up) |
| Nitrite | Urobilinogen (down) |
| Nitrofurantoin | urine colour (yellow-brown); leukocytes (up), protein (up), glucose (down) |
| p-aminosalicylic acid | Protein (up), Urobilinogen (up), Bilirubin (up) |
| Penicillin | Bilirubin (up) |
| Phenazopyridine | Nitrite urine color (orange red) (up), urobilinogen (up), bilirubin (up), blood (up) |
| Phenolphtalein | Urine color (yellow-brown) |
| Phenylketone | Keton (up) |
| Phenytoin | Urine color (brown-red) |
| Phthalein compounds | Ketone (up) |
| Polyvinylpyrrolidone | Protein (up) |
| Mercury salts | Leukocytes (up) |
| Cleaning agents (oxidizing) | Blood (up) |
| Rifampicin | Urine color (red) |
| Hydrochloric acid | Leukocytes (up), Bilirubin (up) |
| Sulfamethoxazole | Urine color (brown-red), urobilinogen (up) |
| Sulfonamide (trimethoprim) | Nitrite (down) |
| Tetracycline | Leukocytes (up) |
| Thiol Groups | Ketone (up), nitrite (down), glucose (up), bilirubin (down), blood (down) |
| Triamteren | Urine color (blue) |
Sources
- Roche Diagnostics Deutschland GmbH (2014): Compendium of Urinalysis. Urine Test Strips and Microscopy, 1-196
- Roche Diagnostics Deutschland GmbH (2009): Nierendiagnostik Grundlagen der Labormedizin, 1-60
- Strotmann, F. (2017): Was der Urin verrät , URL: https://www.pharmazeutische-zeitung.de/ausgabe-152017/was-der-urin-verraet/ , Retrieved 18.06.2019
- Hecker, M.T. & Donskey, C.J. (2014): Is antibiotic treatment indicated in a patient with a positive urine culture but no symptoms? Cleveland Clinic Journal of Medicine, 721-724
- S3-Leitlinie (2017): Epidemiologie, Diagnostik, Therapie und Management unkomplizierter bakterieller ambulant erworbener Harnwegsinfektionen bei erwachsenen Patienten. (AWMF register number: 043-044),
