Is it Normal to have a Small Trace of Bilirubin in Urine?
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The presence of small traces of bilirubin in urine is not considered a normal finding. Bilirubin in urine often denotes an underlying liver or biliary disease.
Keep reading this full guide about the significance of small traces of bilirubin in urine. You will find answers to all your questions.
Is it normal for bilirubin to be in the urine? And what is urine bilirubin’s normal range?
It is not normal for bilirubin to appear in the urine. Having bilirubin in your urine anoanorectalysis (even a small trace or +1) should be investigated.
There is no normal range for bilirubin in urine because bilirubin is not supposed to be present in urine. Therefore, the normal bilirubin result in urine anoanorectalysis is zero or Nil (reference).
The presence of bilirubin in urine indicates an underlying disease in the liver and/or the biliary system. The type of bilirubin that appears in urine is conjugated (direct) bilirubin.
The conjugated or direct bilirubin is water-soluble and can pass in the urine.
Bilirubin is mainly produced by the natural turnover and breakdown of hemoglobin (found in red blood cells).
It is also produced by the breakdown of myoglobin (the chief protein in muscle fibers) and by the degradation of some other enzymes in your body.
Then, bilirubin is processed (conjugated) in the liver to become water-soluble. Finally, it is excreted to the gastrointestinal tract through bile ducts.
Diseases affecting the liver and/or the gallbladder hinder the excretion of bilirubin into the gastrointestinal tract. As a result, bilirubin levels increase in the body and appear in the urine.
What does bilirubin in urine look like?
Small traces of bilirubin is usually unnoticeable by the naked eye. These small traces are only detectable by the urine anoanorectalysis dipsticks.
On the other hand, higher amounts of bilirubin in urine alter the urine color, making it dark. Patients with high bilirubin in urine often describe their urine as tea- or cola-colored.
High bilirubin in urine makes it lose its amber-yellow color and relative transparency. However, small traces of bilirubin either don’t affect the look of urine or only make it slightly dark yellow.
The image below shows what the bilirubin in urine looks like (reference)
What conditions may cause bilirubin to appear in urine?
Conditions that cause bilirubin to appear in urine are either:
- Liver diseases.
- Biliary (bile ducts) diseases.
A. Liver (hepatocellular) causes of bilirubinuria.
1. Hepatocellular disease
- Viral hepatitis (Hepatitis A, B, C, D, or E).
- Alcoholic liver disease (alcoholic steatosis, alcoholic hepatitis, cirrhosis)
- Non-alcoholic steatohepatitis (NASH) or fatty liver disease with inflammation.
- Autoimmune hepatitis: immune-mediated inflammation of the liver.
- Wilson disease: a rare disease of the liver caused by copper overload inside the liver tissue.
- Hemochromatosis: iron overload inside the liver is either due to hereditary causes (primary hemochromatosis) or chronic hemolytic anemia.
2. Hereditary causes (rare).
- Dubin-Johnson syndrome
- Rotor syndrome
3. Primary biliary cirrhosis: a chronic liver disease characterized by destruction of the liver tissues and the biliary ducts.
4. Ischemic hepatitis: cutting off the blood supply to the liver by a vascular obstruction or low blood pressure leading to severe liver inflammation with very high liver enzymes and bilirubin (which appear in urine).
5. Sarcoidosis: A chronic multisystem disease of unclear cause. It may affect the liver and cause jaundice and bilirubinuria.
6. Pregnancy: pregnancy may affect the liver and cause cholestasis (bile stasis), acute fatty liver of pregnancy, and HELLP syndrome.
All the above pregnancy-related liver diseases may cause significant liver dysfunction and cause bilirubin to appear in the urine.
7. Drug-induced liver injury: many drugs affect the liver and may cause significant liver injury (reference).
The table below shows the most common drugs that may cause cholestasis (elevated bilirubin). Review your list of medications and find if there is any of your medications are in the list below.
|Cholestasis without Hepatitis||Cholestasis with Hepatitis||Cholestasis with Bile Duct Injury||Vanishing Bile Duct Syndrome (Ductopenia)||Sclerosing Cholangitis like cholestasis|
|Anabolic steroids Estrogens Tamoxifen Azathioprine Cyclosporine Nevirapine Glimepiride Metolazone Infliximab Cetirizine||Isoniazid Halothane Methyldopa Macrolide antibiotics Tricyclic antidepressants Amoxicillin-clavulanate Azathioprine Oxypenicillins NSAID’s Chlorpromazine Troglitazone Celecoxib Carbamazepine Repaglinide Terbinafine Cephalexin Fenofibrate Hydrochlorothiazides Ticlopidine Pyritinol Methimazole Metformin Gemcitabine Orlistat Celecoxib Gabapentin Propafenone Acitretin Isoflurane Bupropion Captopril Resperidone Propafenone Chlorambucil Risperidone Glimepiride Proplthiouracil Itraconazole Dextromethorphan Atorvastatin Senna Cascara sagrada Lycopodium serratum||Carmustine Toxins: paraquat, methylenedianiline Flucoxacillin Dextropropxyphene Tenoxicam Gold Therapy Pioglitazone Amoxicillin-clavulanate||Aceprometazine Ajmaline Amineptine Amitriptyline Amoxicillin/clavulanic acid Ampicillin Azathioprine Barbiturates Carbamazepine Carbutamide Chlorothiazide Chlorpromazine Cimetidine Ciprofloxacin Clindamycin Co-trimoxazole Cromolyn sodium Cyamemazine Cyclohexyl propionate Cyproheptadine D-penicillamine Diazepam Erythromycin Estradiol Flucloxacillin Glibenclamide Glycyrrhizin Haloperidol Ibuprofen Imipramine Methyltestosterone Norandrostenolone Phenylbutazone Phenytoin Prochlorperazine Terbinafine Tetracyclines Thiabendazole Tiopronin Trifluoperazine Tolbutamide Trimethoprim-sulfamethoxazole Troleandomycin Xenalamine||Floxuridine Intralesional agents: Hypertonic saline, iodine solution, formaldehyde, absolute alcohol, silver nitrate.|
Sepsis is a severe unregulated immune response of the body to infection. It occurs in severe infections and may affect multiple body organs, including the liver. Patients with severe sepsis may have hyperbilirubinemia and bilirubinuria.
B. Biliry cause of bilirubinuria.
- Gallstones inside the common bile duct.
- Biliary stricture (narrowing of the bile ducts)
- Biliary atresia (a congenital condition leading to blockage of the bile ducts).
- Choledochal cyst
- Cholangitis (bacterial, recurrent pyogenic, primary sclerosing, secondary sclerosing)
- Cholangiocarcinoma (cancer affecting the biliary ducts).
- Intrahepatic malignancy compresses the small bile ducts inside the liver.
- Extrahepatic malignancy (lymphoma, pancreatic cancer) compressing the bile ducts.
- Chronic pancreatitis leads to scarring and obstruction of the terminal part of the bile ducts.
Can dehydration cause bilirubin in urine?
Dehydration is not known to cause bilirubin in urine directly. However, it may cause darker-colored urine due to a more concentrated urochrome (the yellow urine pigment) but NOT due to bilirubin in urine.
Can bilirubin in urine be a (false positive) phenomenon?
Bilirubin can be a false positive result in urine due to other substances. These substances are often reddish or brownish and cause a false impression of bilirubin