Bence-Jones protein detection in urine

Definition:-

Henry Bece-Jones described it in 1848. This disorder is seen in 20% patients with multiple  myeloma. Monoclonal light chains are excreted in urine. This is due to asynchronous production of H and L chains or due to deletion of portions of L chains, so that they cannot combined with H chains.

Properties:-

The Bence-Jones protein have the special property of precipitation when heated between 45⁰C and 60⁰C; but redissolving at higher than 80⁰C and lower than 45⁰C.

These proteins may block kidney tubules, leading to renal failure. So,myeloma with Bence-Jones protein has poor prognosis.

Tests:-

A. Screening test for urine Bence-Jones protein

B. Bradshaw's test :- when few ml of urine is layered over few ml of concentrated HCl- white precipitation is formed between two liquids .

C. Serum protein electrophoresis  ( confirmatory test)

Most frequently used test for Bence-Jones protein is heat and acetic acid test.

This test can be done by two methods:-

Method 1.

 1.  5 ml of urine is taken in a test tube and  Acetic acid is mixed

 2. The urine sample is heated.

       If cloudiness appears filter it (other kind of proteinuria are cleaned in this step)

2. The filtrate is then heated till 60⁰C , the precipitate will appear at 45-60⁰C.

3. Boil it till 100⁰C- it disappears.

4. It is cooled down - again it appears at the range of 60- 45⁰C, below 45⁰ it again redissolved.

Result : - presence of Bece- Jones protein

Method 2:-

                                                                                                                                refferencce:-
                                                                      A text book of  biochemistry for medical                                                                                              students by DM  Vasudevan; Web sources.