A: The alternative recommendations below are made in the context of limited quantities of testing supplies during this public health crisis, based on the best available evidence and in consultation with outside experts. We have included a list of examples of products, including catalog numbers for different distributors. The absence of a specific product from this list does not imply unacceptability of that product if it is of the correct type. Other companies may write to FDA at CDRH-EUA-Templates@FDA.HHS.GOV to request their products be included here.
The information provided is not an endorsement of any one product over another of the same type. We note that the information below is not intended to alter any already issued EUA for a COVID-19 diagnostic test nor is it intended to speak to any specific FDA regulatory requirement. Rather, as stated above, the information is being provided to help address availability concerns regarding certain critical components of COVID-19 diagnostic tests during this pandemic.
If you have validated additional alternatives, FDA would like to see your validation data informally through an email to CDRH-EUA-Templates@FDA.HHS.GOV. If FDA's review of validation data indicates that it could be applicable more broadly, and you agree to FDA sharing that information on our website for use by other laboratories, FDA intends to update our FAQs so other laboratories can learn from this validation data.
FDA believes that a nasopharyngeal specimen is the preferred choice for swab-based SARS-CoV-2 testing.
If a nasopharyngeal specimen is not available, then any of the following are acceptable:
Multiple specimens may be taken with a single swab. If a separate swab is used for collecting specimens from two different locations in the same patient, both swabs may be placed in the same vial in order to conserve collection and assay supplies. At this time, anterior nares and mid-turbinate specimen collection are only appropriate for symptomatic patients and both nares should be swabbed. There is currently not enough information to recommend nasal or mid-turbinate testing for asymptomatic persons.
Other swab specimens (i.e., tongue swabs) may have decreased sensitivity, so caution should be exercised when interpreting negative results.
More data are necessary on the validity of buccal swabs or saliva specimens alone.
For patients with productive cough, a sputum sample is an acceptable lower respiratory specimen.
Due to concerns with specimen stability, transport, and appropriate collection materials, self-collection at home or at sites other than designated collection sites staffed by HCPs is currently not recommended.
FDA believes that sample collection with a flocked swab, when available, is preferred. Collection should be conducted with a sterile swab. If the applicator handle requires additional trimming, the trimming should be performed with a sterile pair of scissors to prevent contamination of the sample. Swab recommendations are based on limited available evidence, and expert opinion suggests further research is needed in this area.
Please be aware that the CDC does not recommend use of calcium alginate swabs or swabs with wooden shafts, as they may contain substances that inactivate some viruses and inhibit PCR testing (see https://www.cdc.gov/coronavirus/2019-ncov/lab/guidelines-clinical-specimens.html).
To avoid specimens being wasted, if a lab is presented with a specimen that was collected or identified in a sub-optimal manner, e.g. with a swab for which there is less evidence of effectiveness, FDA believes that it would still be appropriate for the lab to accept the specimen for analysis and note the circumstances on the report. These specimens may have decreased sensitivity, so caution should be exercised when interpreting negative results.
Below is a list of individually wrapped swabs. All swabs are flocked unless noted. Some swabs may be acceptable for specimen collection at multiple locations and are therefore listed under each location.
f Foam swab
** Polyester swab
Additionally, swabs may be provided with transport media as identified below.
VTM/UTM remains the preferred transport media. Examples of universal transport media for viruses and molecular transport media are listed here. All of the products listed below include a nasopharyngeal (NP) flocked swab unless noted otherwise.
* flocked oropharyngeal swab
** Polyester swab
*** no swab
In the absence of VTM/UTM, alternative transport media can be used to collect and transport patient samples for molecular RT-PCR SARS-CoV-2 assays. These recommendations apply to swab-based specimen collection by healthcare providers (HCP), and to anterior nares (nasal) and mid-turbinate specimen collection onsite by self-collection. The best available evidence indicates that these transport media will stabilize the SARS-CoV-2 RNA without meaningful degradation.
Labs can create their own viral transport media. Refer to CDC's SOP#: DSR-052-01: Preparation of Viral Transport Media. Specimens can be stored for up to 72 hours at 4℃.
Liquid Amies media may be used for viral transport when universal transport media is not available. Specimens can be stored in liquid Amies media for up to 72 hours at 4℃. All of the products listed below include a nasopharyngeal (NP) flocked swab unless noted otherwise.
* flocked oropharyngeal swab
*** no swab
Other solutions may also be used for viral transport when universal transport media is not available. FDA recommends use of phosphate buffered saline (PBS), including molecular grade PBS when available, and other similar formulations including Delbecco's PBS, to collect and transport samples for molecular RT-PCR SARS-CoV-2 assays. If PBS is not available, normal saline may be used. FDA believes that a sterile glass or plastic vial containing between 1mL and 3mL of PBS or normal saline is appropriate. Specimens can be stored up to 72 hours at 4℃. All the products listed below are examples of 1-3 mL of normal saline distributed in a vial without a swab.
There is limited data available on test performance with specimens which have been frozen in any transport media; therefore, specimen stability should be investigated if freezing is necessary.