Proteins, nucleic acids are best example of natural polymers. Similarly cellulose is also a natural polymer which acts as main structural component of plants. Usually natural polymers are composed by condensation polymerisation with the elimination of water molecule.
Drug-Laboratory Test Interactions. False-positive urine immunoassay screening tests for phencyclidine (PCP) and amphetamine have been reported in patients taking venlafaxine. This is due to lack of specificity of the screening tests. False positive test results may be expected for several days following discontinuation of venlafaxine therapy. Confirmatory tests, such as GC/MS will clear that misconception up asap...or if you are not using pcp and your dr is sceptical.
When this test is positive and/or the WBC count in urine is high, it may indicate that there is inflammation in the urinary tract or kidneys. The most common cause for WBCs in urine (leukocyturia) is a bacterial urinary tract infection (UTI), such as a bladder or kidney infection. In addition to WBCs, bacteria and RBCs may also be seen in the microscopic examination. If bacteria are present, the chemical test for nitrite may also be positive (see below).