Protein Urine Analysis

Protein in the urine may initially be detected through urinalysis. Larger than normal amounts of protein in the urine is known as proteinuria, or albuminuria. A dipstick test is used to identify substances in the urine including protein. A (UACR) urine albumin to creatine ratio will also detect high protein levels in urine. Urinalysis does not detect the types of proteins that are present; therefore, a physician may recommend, urine immunofixation or urine electrophoresis.

Significance

• Albumin and globulin are two significant proteins. Unusually high, or low amounts of protein in the urine may be an indication of a disorder. Evidence of a disease may be indicated by the amount of albumin and the type and amount of globulin present in the urine. According to the Mayo Clinic, decreased albumin may be a sign of malnutrition, liver disease, kidney disease, inflammatory disease or pregnancy. Elevated albumin may be the indication of dehydration. Decreased globulin levels may be an indication of congenital emphysema, hyperthyroidism or cirrhosis. Elevated globulin levels may be an indication of chronic inflammatory diseases, kidney disease, iron deficiency or multiple myeloma.

Types of Tests

• The dipstick test involves the use of a plastic, or paper dipstick that has been chemically treated. A (UACR) urine albumin to creatine ratio measures the amount of protein in urine compared to creatine. Urine electrophoresis is the process of separating protein in the urine into distinguishable groups. Urine immunofixation is the a method of exposing urine samples to substances followed by the process of urine electrophoresis.

Collection Methods

• There are five different methods of collecting urine: random, early-morning, clear-catch, suprapubic transabdominal needle aspiration and catheterization.

  Random collection is the method of collecting urine anytime the patient is available to provide a sample.

  Early-morning urine collection occurs prior to ingestion of any food. The early-morning urine collection necessitates that the patient avoid ingesting any fluid after six o'clock in the evening the day prior to the test.

  Clear-catch urine collection is a method in which an individual is instructed to release the urine stream and discard the first half of the urine flow. The second half is used as a sample. This method flushes contaminants from the outer part of the urethra.

  Suprapubic transabdominal needle aspiration is a method in which a needle is used to obtain urine from the bladder.

  Catheterization urine collection is a method that is only used in extreme circumstances such as a patient who is confused or comatose.

Function

• The urinalysis, or dipstick test, is used as a screening device in detecting protein in the urine. Urine is placed on the chemically treated dipstick. The indicator dye bromphenol blue is used to detect protein. A sulfosalicylic acid test is also used to detect protein. Urine is centrifuged and sulfosalicylic acid is added. A scale is used to determine the degree of turbidity which is an indicator of the amount of protein present. Another test used to detect high levels of protein in urine is (UACR) urine albumin-to-creatine ratio. It is completed by comparing the amount of albumin to the amount of creatine in the urine. A urine sample that exceeds more that 30 mg of albumin to one gram of creatine is an indication that there may be a problem. Urine electrophoresis analyzes urine protein by separating macromolecules by size and electrical charge which indicates the type of protein present. Immunofixation electrophoresis is a method by which a urine sample is placed in six different positions and treated. Electrophoresis separates proteins by the net charge. An antisera is applied to five of the patterns. A protein fixative is applied to the sixth pattern in order to provide a protein reference. Immunofixation is effective in identifying three variables of the protein. It identifies electrophoretic mobility, antigenic specificity and ratio of proteins.

Warnings

• Protein levels may be increased if an individual has been immunized within six months prior to the test. Drugs such as oral contraceptives and estrogen will falsely elevate protein levels. Aspirin, bicarbonates, chlorpromazine, porazine, corticosteroids and neomycin may affect protein electrophoresis results as well. It is important for individuals to tell their physician about all medications they are taking prior to undergoing any tests.