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We measured cortisol and cortisone in plasma--both total and free--and in saliva during the course of pregnancy and postpartum. Antepartum and postpartum concentrations and morning and afternoon concentrations of both steroids were compared. The mean concentrations of cortisol and cortisone increased towards term and were significantly greater at the end of pregnancy than postpartum, except for free cortisol in plasma in the afternoon. The daily rhythm of both steroids was maintained throughout pregnancy and postpartum. The correlations between salivary and plasma free concentrations of cortisol and cortisone as well as of the sum of cortisol + cortisone were highly significant. The mean concentrations of cortisone in saliva accurately reflected both total and free concentrations in plasma. For cortisol, however, the change of the concentrations in saliva, was somewhat different from that in plasma. Moreover, the mass ratio of plasma free cortisol to salivary cortisol was about 2, whereas for cortisone the ratio was only about 0.5, probably owing to the conversion of cortisol to cortisone by 11 beta-hydroxysteroid dehydrogenase in the salivary gland. Furthermore, the passage of cortisol and cortisone from plasma to saliva should not be regarded as simple diffusion, because in the first half of pregnancy the sum of the concentrations of cortisol + cortisone in saliva significantly exceeded the sum of their free concentrations in plasma.

After extraction of the sample (on filter paper) in the counting vial, cortisol is assayed by adding 50 microL of horse serum containing tritiated cortisol, and 2 mL of toluene scintillator, shaking for 20 min, and counting the radioactivity in a liquid-scintillation counter at ambient temperature. The method can be applied to saliva, serum, or urine--directly as wet samples or dried on the filter paper. Only inexpensive reagents, which are stable for months to years, are needed.

Saliva-based tests are not new. The Chinese used saliva for an ancient polygraph called the rice test, in which an interrogator placed grains of dry rice into the mouth of a suspect and asked the suspect to spit out the rice. If the grains of rice stuck to the mouth of the suspect, stress-induced xerostomia was assumed—and therefore the suspect was guilty. Fortunately, over the past 3000 years, we have made progress in salivary diagnostics. One of the latest advances is the design of a new paper-based immunoassay by Jackie Y. Ying, executive director of the Institute of Bioengineering and Nanotechnology in Singapore. The home pregnancy test is an example of a traditional paper-based immunoassay, known as the lateral flow test. In such a test, the sample flows laterally through the test strip by capillary action. The sample comes in contact with particles with which it can react as it migrates through the strip. This design is popular because of its simplicity and low cost. Jackie Y. Ying However, although saliva is a rich source of biomarkers, its use in rapid tests has been complicated by proteinaceous products in saliva that interfere with lateral flow reactions. According to George Whitesides of Harvard University, “the basic lateral flow …

We review the status of radioimmunoassays for detection of abused drugs. Individual assays with use of 125I-labeled antigens are all performed in an identical manner and can be completed in 30 min to 1 h. Combined assays for simultaneous detection of two or more such drugs or assays in which a tritium-labeled antigen is used require 1-2 h for completion. All tests can be performed with 0.1 ml or less of specimen. The assays involving 125I reliably detect urinary concentrations of, per liter, 40-100 mug of morphine, 100 mug of barbiturates, methadone, methaqualone, or benzoylecgonine, and 1000 mug of amphetamine. The assay for morphine involving 3H detects 60 mug/liter. Each assay is capable of providing a qualitative and quantitative estimate of the drugs sought. The 125I-labeled antigens have a usable shelf life of at least two to four months after the antigen is iodinated; the tritium assay is stable for six months. The assays can be performed with use of paper discs that have been suspended in urine and then dried, in place of the liquid specimen. The assays appear to be equally applicable to detection of drugs in urine, blood, saliva, and tissues. All of them are done at ambient temperature and can be used equally well for emergency (stat) tests or mass screening. Except for the benzoylecgonine assay, the clinical reliability of these tests has been demonstrated.

We review the status of radioimmunoassays for detection of abused drugs. Individual assays with use of 125I-labeled antigens are all performed in an identical manner and can be completed in 30 min to 1 h. Combined assays for simultaneous detection of two or more such drugs or assays in which a tritium-labeled antigen is used require 1-2 h for completion. All tests can be performed with 0.1 ml or less of specimen. The assays involving 125I reliably detect urinary concentrations of, per liter, 40-100 mug of morphine, 100 mug of barbiturates, methadone, methaqualone, or benzoylecgonine, and 1000 mug of amphetamine. The assay for morphine involving 3H detects 60 mug/liter. Each assay is capable of providing a qualitative and quantitative estimate of the drugs sought. The 125I-labeled antigens have a usable shelf life of at least two to four months after the antigen is iodinated; the tritium assay is stable for six months. The assays can be performed with use of paper discs that have been suspended in urine and then dried, in place of the liquid specimen. The assays appear to be equally applicable to detection of drugs in urine, blood, saliva, and tissues. All of them are done at ambient temperature and can be used equally well for emergency (stat) tests or mass screening. Except for the benzoylecgonine assay, the clinical reliability of these tests has been demonstrated.