Precipitation Information and Courses from MediaLab, Inc.
These are the MediaLab courses that cover Precipitation and links to relevant pages within the course.
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| Which of the following tests confirms the presence of Bence-Jones proteinuria: | View Page |
| Which of the following methods is not a quantitative method for the determination of
albumin: | View Page |
| Which of the following methods may be employed to definitively identify Bence-Jones proteins: | View Page |
| Which of the following would be the most appropriate method to confirm a positive
protein from a urine dipstick: | View Page |
| The reaction that occurs when a soluble antigen is mixed with its specific antibody is termed: | View Page |
| The intracellular precipitates seen in the RBCs in this illustration is termed: | View Page |
| Screening and Secondary Tests for Protein A routine reagent strip protein method, based on the principle of "protein error of indicators," produces a visible colorimetric reaction that is capable of detecting most instances of proteinuria.Traditionally, laboratories have used sulfosalicylic acid (SSA) to confirm all positive protein reagent strip results, but this practice is not as common in today's laboratories. SSA is a precipitation method that reacts with all forms of protein. However, any substance that is precipitated by acid will produce false-positive SSA results. This includes radiographic dyes, cephalosporins, penicillins, and sulfonamides. SSA may be used as a secondary protein detection method if the urine is highly alkaline (pH of 9.0 or greater) which would overwhelm the buffering capacity of the reagent on the protein reagent stick. SSA may also be used as an alternative protein detection method if the urine is highly colored so that the colorimetric reaction is masked on the reagent strip. | View Page |
| The screening test most commonly used to detect Bence-Jones protein in urine is: | View Page |
| A routine reagent strip test for protein is based on the principle of: | View Page |
| Heat and Acid Test for Urinary Protein The heat and acetic acid test is another semiquantitative test used to confirm the presence of protein in urine. It is more sensitive than the SSA test because the pH of the sample is brought close to the isoelectric point of proteins. However, this test is sometimes considered too sensitive because it can detect trace amounts of protein which are considered normal. The heat and acetic acid test gives false positive results with inorganic iodides, benzoin, tolutamide, and proteoses, similar to the SSA test. Bence-Jones protein consists of dimers of either kappa or lambda light chains from immunoglobulins. This abnormal protein is most often associated with multiple myeloma, but can also be found in cases of lymphoma, macroglobulinemia, leukemia, and other malignancies (Balant and Fabre, 1978). Testing for Bence-Jones protein is not part of the routine urinalysis. However, if Bence-Jones protein is suspected, the heat precipitation test or immunoelectrophoresis can be performed on a urine specimen. The heat precipitation test is based on the protein’s unusual solubility properties. Bence-Jones protein precipitates at temperatures between 40ºC and 60ºC (56ºC optimum), but dissolves again at 100ºC. Upon cooling, the precipitate will reappear around 60ºC and will dissolve again below 40ºC | View Page |
| Confirmatory and Secondary Tests The following confirmatory or secondary tests are covered in this unit: Clinitest®Sulfosalicylic Acid Precipitation TestMicroalbumin Reagent Strip TestAcetest®Ictotest® | View Page |