You have completed your annual physical, provided the obligatory urine specimen, and proceed to the rest of your day. Later you receive a phone call asking you to return to the clinic. Once there, the doctor informs you that he has noticed some bilirubinuria and wants to run more tests. What is bilirubinuria, and how concerned should you be?
According to Wikipedia, bilirubinuria is described as an abnormality of the urine caused by high levels of conjugated bilirubin. The doctor's first clue is the dark brownish-amber color of the urine. Small amounts of bilirubin should be present, and accounts for the normal yellow color. A large amount, however, is always an abnormality, and should be investigated immediately.
Bilirubinuria is not a disease, but an abnormality that indicates a possible problem. It may indicate any of several conditions, including jaundice, hepatitis or other hepatic diseases, liver dysfunction or impairment, disorders involving hemolytic anemia, bile duct obstruction, starvation or dehydration, hemolysis, or pyrexia. In more rare cases in may be a symptom of certain cancers, or inherited disorders such as Dubin-Johnson Syndrome or Rotor Syndrome. It may also be a false positive reading, caused by certain prescribed drugs that lower the urine pH value, or high levels of nitrites or ascorbic acid.
Given the possibilities you should always be concerned, and take immediate steps to find the underlying cause of the bilirubinuria. You should also not panic. First, it may be a false-positive test, and subsequent testing will show this. Second, the cause may be more incidental; you have had a recent illness, injury or surgery that is causing fluctuations in the amounts of red blood cells your body is metabolizing, or you worked outside in the hot sun all day and didn't drink enough water. Third, if it is symptomatic of a more serious problem, it is an early indicator. You and your doctor can now find the problem when it is most advantageous in terms of correcting it.
To better understand bilirubinuria, it is helpful to have at least a basic understanding of bilirubin. Your body produces new red blood cells on a daily basis. They replace old or damaged ones, which go to the spleen for disposal. Here hemoglobin is released. The globins are turned into amino acids and used by the body. The heme is turned into unconjugated bilirubin and sent to the liver. Here it is conjugated, or made soluble in water, and sent to the intestines. Most of it is excreted as bile, but some remains in the large intestine to be further metabolized before finally being excreted as feces. A small amount will also excrete in the urine.
Each of these processes involves adding another component to metabolize it, which slightly changes its makeup. Further testing to rule out false-positives and incidental causes will be done. Then, more specific tests will look for these metabolized substances, like urobilinogen, for instance. The results will give doctors a better clue as to what part of the body is not functioning correctly. Other symptoms, like jaundice, abnormal stools, or distended abdomen, will be looked for to further pinpoint the problem. Your doctors may want to do blood tests to look for abnormal phosphatase levels or other symptoms. They may suggest an ultrasound, CT scan, MRI scan, a liver biopsy, or other procedures.
Like many symptoms, bilirubinuria is a clinically important finding because it can lead doctors to early detection of a significant disorder. It can also mean very little. It is not one you can afford to ignore, but it should also not make you hyperventilate. Use common sense, do your own research, and work with your doctor to find and correct the problem.