In recent years, the use of saliva tests has become more prevalent in a variety of health-related fields. Saliva tests are used to determine the presence of various substances in the body, such as drugs, hormones, and other compounds. However, there has been significant controversy surrounding the accuracy of saliva tests. In this article, we will explore the science behind saliva tests and separate fact from fiction when it comes to their accuracy.
What are Saliva Tests?
Saliva tests are laboratory-based or portable devices used to analyze biological samples for various substances, such as drugs, hormones, or other compounds that may be present in the saliva. These tests are utilized for different purposes, such as forensic analysis, drug screening, and monitoring of hormone levels or infectious diseases. Saliva tests, also called oral fluid tests, are non-invasive, painless, and easy to use which makes it popular among doctors and patients alike.
How do Saliva Tests Work?
Saliva tests works on the principle of enzymes and antibodies which are present in the saliva. These enzymes and antibodies bind to specific chemicals, metabolites, and other substances present in the saliva. The saliva sample is collected from the subject through a collection device, which could be a swab, sponge or a tube. The collected specimen is then transported to a lab, where it is subjected to complex biochemical analysis. As the chemicals in the saliva bind to the enzymes and antibodies present in the test, this produces a reaction that can be measured and quantified. Based on these measurements, researchers can determine the presence and levels of specific substances in the saliva sample.
Saliva Vs. Blood and Urine Tests
One of the most significant advantages of saliva tests over urine or blood tests is that it is non-invasive and much easier to administer, which means patients are more likely to comply with these tests compared to more invasive methods. Saliva tests are also less costly than blood tests and reduce the risk of infection as there is no need for syringe needles or blood drawing. Additionally, these tests can be performed quickly, and there are no preparation procedures that are required before the test, like strict diet plans or fasting periods.
Although there are some advantages, saliva tests may not always be better than blood and urine tests. In certain cases, the levels of the target analyte in saliva differ from that found in blood or urine, and this can lead to an inaccurate diagnosis or result. The concentrations of some substances, such as drugs, may be lower in saliva than in blood or urine, which can lead to a false-negative result. However, saliva testing for drugs of abuse has proved to be more reliable than urine testing, mainly because drugs remain in saliva for a longer time than urine’s presence.
Factors that can Affect Saliva Testing Accuracy
Timing of Sample Collection
The timing of the sample collection can significantly affect the accuracy of saliva test results. For example, samples collected very early in the morning may have higher hormone levels than later in the day, and this affect may occur due to diurnal variation, which causes chemical changes throughout the day. The time of the last meal may also affect test results, mainly if the test involves glucose levels. Drugs, beverages, and smoking can also interfere with saliva test results.
Quality of Sample Collection
The quality of the saliva sample collection is also critical. Improper collection techniques, storage conditions, lab analysis, and a lack of precision during analysis can all contribute to inaccurate results. For instance, food debris, bacteria, or other substances in the mouth that mix with the sample could interfere with the analysis, leading to false results.
Subject’s Age and Gender
Age and gender can also affect the accuracy of saliva tests. Research shows that hormone levels differ between males and females, and age could affect hormone levels associated with certain medical conditions such as menopause or puberty. Therefore, to ensure the most accurate results, researchers and clinicians must consider age and gender variation in hormone levels during saliva testing analysis.
Oral Health
Oral health issues can also affect the reliability of saliva testing. Conditions like gingivitis, periodontitis, or other gum diseases can interfere with the analysis, leading to inaccurate results. Lack of oral hygiene can compromise the quality of the saliva sample, leading to contamination and interference with the test results.
The Accuracy of Saliva Tests
The accuracy of saliva tests depends on the type of test performed, the substance being tested, and many other factors. The science behind saliva testing has unquestionably improved in recent years, but as with any testing method, there is a possibility for false results.
Drug Screening and Saliva Tests
The accuracy of saliva tests used for drug screening appears to vary depending on the specific substance being tested, the sensitivity of the test, and the test’s brand. According to research from the Substance Abuse and Mental Health Services Administration (SAMHSA), saliva tests for drugs are very accurate and effective for determining whether a person has used drugs within the previous 24-72 hours. This accuracy time frame varies depending on the substance being tested and varies from hours to weeks.
Hormone Testing and Saliva Tests
Saliva tests have been popular over the years to measure hormone levels in the body. Testing hormones in saliva allow easier collection of data, which repeatedly measures different hormones through the day. Hormones measured through this methodology are cortisol, testosterone, progesterone, estradiol, melatonin, etc. However, the tests’ accuracy and reliability still pose a matter of debate within the scientific community mainly due to the factors discussed above.
Advantages and Disadvantages of Saliva Testing
- Advantages:
- Easier to use and less invasive than blood or urine tests
- Non-invasive
- Less costly than other testing methods
- Reduces the risk of infection transmission as there is no need for needles or blood drawing
- Can be performed quickly
- Smaller sample volume makes the sample less complicated.
- Disadvantages:
- Less research on technique in the laboratory
- Accuracy can be affected by diet, oral health, and other personal factors mentioned above
- The analyte concentration in saliva may differ from other fluid, which may lead to false interpretations.
The Future of Saliva Testing
Despite the concerns about the accuracy of saliva tests, the science behind it is evolving at a rapid pace. With the advancements in technology, the accuracy of saliva testing will likely continue to improve over time. This improvement can revolutionize the way saliva samples are collected, analyzed, and used in the medical field.
Portable Devices
New technologies such as portable devices have been developed to analyze saliva in real-time for instant results. Such devices could have significant applications for various industries such as sports, where medical personnel can check for any prohibited drug use, and avoid an accident by allowing instant testing. Portable devices can be used not just for doping but also for medical records where patients’ hormone level or drug dosage can be measured.
Sensitive Methodologies
New and more sensitive methodologies have been introduced to analyze biomarkers in saliva to aid in disease detection, such as the diagnosis of chronic diseases like cancer and diabetes. Such technologies have high sensitivity and specificity, which can lead to early detection of diseases for improved treatment outcomes.
Conclusion
Saliva tests have been gaining popularity over the years, and while they are not entirely free from limitations, they are easy to use, non-invasive, and less costly than other testing methodologies. The accuracy of saliva tests can be affected by numerous personal, genetic, and manufacturing factors, and it is essential to consider these factors when interpreting the test results. As the technology behind saliva tests continues to evolve, the accuracy and reliability of saliva testing will likely continue to improve.
List of FAQs on Saliva Tests
- Q: How long do drugs stay in your saliva?
- Q: Can I drink water before a saliva drug test?
- Q: Are saliva hormone tests reliable?
- Q: How many days of abstinence are required for saliva drug testing?
- Q: Can saliva testing detect HIV?
A: Drugs can stay in saliva for different periods, ranging from a few hours to a few days or even weeks, depending on the type of chemical involved.
A: Yes, you can drink water before a test, but not drink other fluids like alcohol which can alter the test result.
A: Although saliva hormones tests are popular and convenient, their accuracy and reliability remain matters of debate in the scientific community, despite research to support their use.
A: A minimum of 24-72 hours of negation of the drug use is required, depending on the substance being tested, for the best testing results.
A: Yes, saliva testing can detect HIV, but it is not the recommended testing method by healthcare professionals for diagnosing HIV as blood and urine testing method has greater accuracy and reliability.
References
- Aitchison, K. J., Gonzalez-Chica, D. A., Sawyer, M. G., & Baghurst, P. A. (2011). Salivary cortisol measurement: a practical approach to assess cortisol levels in clinical and research settings. Clinical biochemistry, 44(4), 300-305.
- Jenkins, S. A., & Maguire, A. M. (2011). Are saliva hormone measurements valid?–comparison of salivary and serum measurements of oestradiol and testosterone female circus artists performing four shows during their menstrual cycle. Journal of Strength and Conditioning Research, 25(1), 25-32.
- Murphy, W. H., & Hammett-Stabler, C. A. (2011). Applications of saliva drug testing in the medical field. Expert review of molecular diagnostics, 11(4), 393-399.
- Nyirő, G., & Bencsik, T. (2017). Saliva as a diagnostic tool in various medical fields. Orvosi hetilap, 158(18), 683-690.