salivary cortisol

Measurement of cortisol levels in nighttime saliva has excellent specificity and sensitivity for screening Cushing's syndrome. The saliva component accounts for more than 99% of water, of which organic matter accounts for about 0.5%, and inorganic matter accounts for about 0.2%. In addition, there are a small number of red blood cells, epithelial cells and the like. There are many factors affecting salivation, such as internal and external factors. Therefore, the saliva composition is not constant enough, and the collection time is preferably limited to 2 to 4 hours in the afternoon. Basic Information Specialist classification: oral examination classification: body fluid examination Applicable gender: whether men and women apply fasting: fasting Analysis results: Below normal: Found in adrenal cortical tuberculosis and atrophy, pituitary hypofunction, hypothyroidism, chronic wasting disease, amyloidosis, leukemia, congenital adrenal hyperplasia, CBG (corticosterone-binding globulin) deficiency. Normal value: Salivary cortisol: 8.39-8.99nmol/L Above normal: Found in adrenal hyperplasia, tumors (such as adrenal adenoma, pancreatic cancer, thyroid cancer, testicular cancer, breast cancer), simple obesity, surgery, trauma, myocardial infarction, oat cell lung cancer, hyperthyroidism and so on. negative: Positive: Tips: Apply warm water to the saliva when collecting saliva, and collect it 5 to 10 minutes after the completion. Normal value 8.39 to 8.99 nmol/L. Clinical significance 1, lower Found in adrenal cortical tuberculosis and atrophy, pituitary hypofunction, hypothyroidism, chronic wasting disease, amyloidosis, leukemia, congenital adrenal hyperplasia, CBG (corticosterone-binding globulin) deficiency. 2, rise Found in adrenal hyperplasia, tumors (such as adrenal adenoma, pancreatic cancer, thyroid cancer, testicular cancer, breast cancer), simple obesity, surgery, trauma, myocardial infarction, oat cell lung cancer, hyperthyroidism and so on. Low results may be diseases: congenital adrenal hyperplasia considerations When collecting saliva, apply warm water to rinse the mouth, and collect it 5 to 10 minutes after the completion. At the time of collection, the catheter can be directly used to draw from the opening of each gland, or the naturally flowing saliva can be collected in a clean test tube. If it is not easy to naturally shed saliva, use a small amount of sterile cotton wool to put it under the tongue for a few minutes, and take out the squeezed cotton ball to get saliva. Inspection process The method is divided into three steps, namely antigen-antibody reaction, B and F separation, and radioactivity determination. 1, antigen and antibody reaction The specimen (non-labeled antigen), labeled antigen and antiserum were sequentially dosed into a small test tube, and allowed to stand at room temperature (15 to 30 ° C) for 24 hours to fully compete for binding. 2, B, F separation There are many separation techniques, and the precipitation method is commonly used. (1) Second antibody precipitation method: also known as diabody method, after the test antigen specifically reacts with the first antibody, the corresponding second antibody is added, so that the formed antigen-first antibody-second antibody complex The precipitated antigen B is separated from the free antigen F by centrifugation. This method is a specific precipitation, complete separation, low non-specific binding. However, the amount of the second antibody is large and the cost is high. In addition, the concentration of the specimen and the presence or absence of the anticoagulant can affect the results to some extent. (2) Polyethylene glycol (PEG) precipitation method: the protein is in an isoelectric point state, and the hydration layer is destroyed to cause protein precipitation. The advantage of this method is that PEG is convenient to prepare, inexpensive, and rapid to separate. The disadvantage is that there are many non-specific precipitates and the separation is incomplete. (3) Second antibody-polyethylene glycol precipitation method: This method not only has the advantage of rapid precipitation of PEG method, but also maintains the effect of specific precipitation of second antibody, reduces the amount of second antibody, and reduces the concentration of PEG, so that Specific precipitates are reduced. (4) Activated carbon adsorption method: The free part of the small molecule is adsorbed by the surface activity of the activated carbon. For example, a layer of dextran is coated on the surface of the activated carbon to make a mesh having a certain pore diameter on the surface, thereby allowing small molecules of free antigen or hapten to escape and being adsorbed, while the macromolecular complex is excluded. After the antigen and the antibody are reacted, the dextran-activated carbon is added and allowed to stand for 5 to 10 minutes, so that the free antigen is adsorbed on the activated carbon particles, and the particles are precipitated by centrifugation, and the supernatant contains the labeled antigen. 3. Determination of radioactivity After separation of B and F, the radioactivity can be measured. There are two types of measuring instruments: a liquid scintillation counter (measuring beta rays) and a crystal scintillation counter (measuring gamma rays). The unit of counting is the number of electrical pulses output by the detector in units of cpm (number of pulses/min). A standard curve is required for each measurement, and the different concentrations of the standard antigen are plotted on the abscissa, and the corresponding radioactivity measured is plotted on the ordinate. The radioactivity may be optionally B or F, and the calculated values ​​B/B+F, B/F or B/B0 may also be used. Specimens should be determined in duplicate, the average value is taken, and the corresponding antigen concentration is detected on the standard curve. Not suitable for the crowd no. Adverse reactions and risks no.

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