Direct-to-consumer (DTC) laboratory testing permits consumers to order laboratory tests directly from a clinical laboratory without necessarily having to work with their healthcare provider. Currently nearly 40 states allow consumers to order some or all of their laboratory tests. This model of lab testing is relatively new in the United States and little is known about its impact on consumers.
However, many health care providers are concerned that consumers do not have enough background knowledge and information to make sound decisions based on their test results. Consumers might not understand what tests to order or how to interpret the tests. It is unclear how often consumers share their results with healthcare providers and what action, if any, is taken based on the results. In addition, frequent test ordering in a normal population increases the chances of false (positive and negative) results. False results may give consumers a false sense of security when tests are normal or result in unnecessary alarm when tests are abnormal.
Recently an article in the medical journal JAMA expressed the opinions of many in the medical field that DTC testing may actually increase the cost of healthcare in the US.
However, many feel that there is value in allowing consumers to order laboratory tests through DTC laboratories and that there is not enough data to conclude that DTC testing adversely affects patient health or healthcare costs. This was expressed in a response to the JAMA article.
In order to gather data on the effects of DTC laboratory testing, a survey is being conducted to identify the reasons American consumers use DTC laboratories. The survey will quantify how frequently consumers of DTC test services order tests, define the most frequently ordered DTC tests, identify resources consumers use to understand DTC test results, and evaluate consumer engagement with health care professionals based on DTC test results.
If you have ever ordered your own lab tests from a direct-to-consumer laboratory, you may be eligible to participate in a research study from Washington University about direct-to-consumer lab testing.
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to learn more or contact Dr. Ann Gronowski at 314-362-0194.
We have previously blogged about testing for Zika virus in pregnant women here and here. But testing recommendations continue to evolve.
As a result of increasing knowledge about the Zika virus, the CDC updated their recommendations. The changes are based on declining trends in the number of reported cases of Zika virus infection in the Americas, emerging evidence on prolonged detection of Zika IgM antibodies, and new limitations for interpreting serologic tests during pregnancy. IgM is most likely to be detected in the first 12 weeks after infection but may persist beyond 12 weeks in some infected individuals, limiting the ability of testing to determine whether an infection occurred during or prior to pregnancy. False positive results and cross-reactivity with other flaviviruses can occur with IgM assays. Therefore, it is important to ascertain whether a woman had exposure to flaviviruses other than Zika virus before the current pregnancy because a positive IgM result might have been caused by cross-reactivity from a previous flavivirus exposure. Given the possibility of a false positive result, laboratory test results should not be released until all testing is complete.
Zika virus tests should be performed in:
- Symptomatic pregnant women with possible exposure to Zika virus
- Asymptomatic pregnant women with ongoing possible exposure to Zika virus
- Pregnant women with possible exposure to Zika virus who have a fetus with prenatal ultrasound findings consistent with congenital Zika virus infection
- Non-pregnant symptomatic individuals with possible exposure to areas with risk of Zika virus transmission
Zika virus testing may be considered for:
- Asymptomatic pregnant women with recent possible but no ongoing exposure to Zika virus (i.e., travelers). Although not routinely recommended, testing may be considered on a case-by-case basis and in line with jurisdictional recommendations.
Zika virus testing is not recommended for:
- Non-pregnant asymptomatic individuals
- Pre-conception screening
The primary specimens for Zika virus testing should be paired serum and urine samples. Some emergency authorization tests may require other samples types. However, serum should always be obtained in case nucleic acid testing (NAT) testing is indicated after initial test results. NAT (on serum and urine) and IgM serological testing should be performed concurrently when testing symptomatic pregnant women. Specific guidance for laboratories is given by the CDC.