Methods for determining the protein in the urine

Many diseases occur without significant clinical manifestations, so the determination of protein in the urine with the purpose of timely detection and treatment of the pathological condition is an important point for practical medicine.

Protein in urine can be determined by qualitative and quantitative methods.

Qualitative methods

At the moment there are about 100 known qualitative reactions to protein. They consist in precipitation of a protein by physical or chemical influences. With a positive reaction, turbidity develops.

The most informative samples are:

1. With sulfosalicylic acid. It is considered the most sensitive and with its help it is possible to determine even the smallest amounts of protein bodies in the urine. The description of the result with the trace presence of the protein is denoted by the term "opalescence", and with a larger amount - "weakly positive", "positive" and with a large loss of protein in the urine - "a strongly positive reaction".
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2. With an acid substitute - aseptol. A solution of the substance is added to the urine, and when the ring forms on the solution boundary, it is said that the sample is positive.
3. Geller. Produced by a solution of nitric acid. The result of the treatment is treated similarly to that with aseptol. Sometimes the ring can be during the presence of urate in the test liquid.
4. With acetic acid with the addition of moth-sulfosodium-potassium. With a high concentration of urine when carrying out such a sample, it is diluted, otherwise a false positive result may result, since the reaction will be on urate and uric acid.

Improperly performing such a test can often give the wrong result in newborn babies, since urine is formed with a high content of uric acid.

The basic rules for carrying out the tests are as follows: it is necessary that the test urine is clear, had a weakly acid medium( for this, a small amount of acetic acid is sometimes added), the test tubes must be two for monitoring.

Quantitation of

When a urinalysis is performed, the total protein is determined by quantitative methods. There are a lot of them, but most often the following are used:

1. Esbakh method. It is used since the 19th century. To do this, urine and reagent are poured into a certain test tube. Then the mixture is shaken a little, and left in closed form for 24-48 hours. The resulting precipitate is considered to be divided into a test tube. The correct conclusion can be made only with acid urine. Such a technique is quite simple, but it does not have high accuracy and it takes time.
2. The Brandberg-Stolnikov method. Based on Geller's test, which allows to obtain a result with a protein concentration of more than 3.3 mg%.Later, this method was modified and simplified.
3. Nephelometric methods for determining the amount of protein are widely used.

For a complete understanding of the amount of protein, it is best to use a urine test for daily protein.

For the correct result, the first morning portion pours out, the collection begins with the second portion in one container, which is recommended to be kept in the refrigerator.

The last portion is collected in the morning. After this, it is necessary to measure the volume, then mix thoroughly, and pour into a jar a portion of not more than 50ml. This capacity should be taken to the laboratory. On a special form, you need to indicate the results of the total daily urine volume, as well as the height and weight of the patient.

Application of test strips

The test for protein in the urine acts on the principle of indicators. Special strips can change their color depending on the protein concentration. They are convenient for determining changes that occur at different times, and are used both in the home and in any medical and preventive care settings.

Test urinary strips are used when it is necessary to early determine and track the results of treatment for urogenital pathologies. This diagnostic technique is sensitive, and reacts to albumin at its concentration of 0.1 g / l, and allows to determine qualitative and semiquantitative changes in urinary protein content.

Based on the results of this diagnosis, you can monitor the effectiveness of the therapy, amend it, and prescribe the necessary diet.

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