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What is Bence Jones Protein test?

Bence Jones Proteins (BJP) are abnormal fragments of antibodies (proteins) found either in blood or urine. In healthy conditions, BJP fragments are not present independently in the body; instead, they are a part of the antibodies, which are too large to be filtered through the kidneys. However, in certain conditions, there can be increased production of independent BJP, which are small enough to be filtered through kidneys. Consequently, in such conditions, BJP will be present as an independent protein in blood as well as in urine as it gets filtered through kidneys.

Increased production of BJP can occur due to a tumour in  BJP-producing cells such as multiple myeloma. Thus, BJP test is used to diagnose the presence of a tumour. These tumours are generally related to the fighter (plasma) cells of the body, whose function is to produce antibodies. Tumours in fighter cells can also cause bone damage and increase calcium in blood. This would also affect kidneys. 

  1. Why is Bence Jones Protein test performed?
  2. How do you prepare for Bence Jones Protein test?
  3. How is Bence Jones Protein test performed?
  4. What do Bence Jones Protein test results mean?

A doctor may order a BJP test under the following conditions:

  • Suspected myeloma
  • To check for myeloma treatment progression
  • Kidney dysfunction
  • High levels of calcium in blood
  • Bone fracture or bone pain
  • Reduction in the level of red blood cells, white blood cells or platelets
  • Weakness in legs
  • Problems with the nervous system
  • A high number of infections

Myeloma is a tumour of plasma cells. When tumour cells increase in number, they will produce increased amounts of BJP. Therefore, levels of BJP in blood can be correlated with tumour growth. During the treatment of this condition, BJP production will reduce gradually, which will be reflected in blood and urine. Thus, a BJP test can be used to monitor tumour treatment too.

Accumulation of BJP in blood affects kidney function. Therefore, progressive kidney damage may be seen along with thirst and excess urination.

BJP levels are primarily checked in urine, although sometimes blood levels of BJP can also be checked. No special precautions or preparation is required for these tests as a sample can be collected at any time. It is crucial for the individual to let the doctor know if they have any medical conditions or are taking any prescription medications or herbal supplements.

A regular urine sample can be taken from the individual at any time in the day. It is recommended that the individual clean their private areas properly before depositing the sample in the collection cup provided. This will assure that any germs from the vagina/penis do not enter the urine. The collected sample is sent to a laboratory for testing.

Normal results:

Normal tests results of BJP tests mean that there is no BJP in the provided urine sample and the person may not have a tumour or kidney disorder. The doctor may still order other tests to confirm the result if he/she suspects other underlying conditions.

Abnormal results:

Results of a this test are considered to be abnormal when BJP is found in the provided urine sample. This could indicate various conditions like:

  • Multiple myeloma - tumour of plasma cells
  • Monoclonal gammopathy of undetermined significance - increased unexplained antibody production in the absence of tumour
  • Renal impairment - kidney dysfunction due to deposition of excess BJP
  • Lymphoma - tumour of lymphocytes like B cells
  • Amyloid deposition - accumulation of protein in various tissues or organs of the body
  • Fanconi syndrome - functional failure of the kidney tubules
  • Disorders associated with the peripheral nerves, for example, carpal tunnel syndrome

Presence of BJP in the urine is not the sole diagnostic factor for the conditions mentioned above, and the doctor may order more tests to confirm the diagnosis.

Disclaimer: All results must be clinically correlated with the patient’s complaints to make a complete and accurate diagnosis. The above information is provided from a purely educational point of view and is in no way a substitute for medical advice by a qualified doctor.

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References

  1. Marshal W.J, Lapsley M, Day A.P, Ayling R.M. Clinical biochemistry: Metabolic and clinical aspects. 3rd ed. Churchill Livingstone: Elsevier; 2014. Chapter 8, Proteinuria, p.163—175.
  2. University of Rochester Medical Center [Internet]. Rochester (NY): University of Rochester Medical Center; Bence-Jones Protein (Urine)
  3. Provan D, Oxford Handbook of Clinical and Laboratory Investigation. 4th ed. United Kingdom: Oxford University Press; 2018. Chapter 10, Renal Medicine; p.660.
  4. Riley RS, McPherson RA. Henry's Clinical Diagnosis and Management by Laboratory Methods. 23rd ed. Philadelphia, PA: Elsevier; 2017. Chap 28, Basic examination of urine.
  5. Chernecky CC, Berger BJ. Laboratory Tests and Diagnostic Procedures. 6th ed. Philadelphia, PA: Elsevier; 2013. Protein electrophoresis – urine, p. 920—923.
  6. Marshal W.J, Lapsley M, Day A.P, Ayling R.M. Clinical biochemistry: Metabolic and clinical aspects. 3rd ed. Churchill Livingstone: Elsevier; 2014. Chapter 30, Immunology for clinical biochemists, p.588—590.
  7. Marshal W.J, Lapsley M, Day A.P, Ayling R.M. Clinical biochemistry: Metabolic and clinical aspects. 3rd ed. Churchill Livingstone: Elsevier; 2014. Chapter 36, Biochemical aspects of neurological disease, p.659—696.