Antibody Tests for US Travel: What You Need to Know
Understanding Antibody Tests
Antibody tests—also called serology tests—find antibodies in your blood. Proteins your immune system produces to combat diseases such as COVID-19 are antibodies. A positive antibody test results from past vaccination or infection. It does not point to a present infection. The two primary forms are:
Binding antibody tests: These identify the presence of antibodies but don't measure how well they work.
Neutralizing antibody tests detect antibodies that block the virus from infecting cells. They are mainly used in research.
Antibody Tests and COVID-19
Initially tracking the spread of COVID-19 and helping to identify those with past infections, antibody tests have had little influence on travel. Although antibodies provide some degree of protection, it is not always clear how long immunity lasts or how successful it is against new variations.
The CDC and other health agencies do not advise Using antibody tests to determine whether you require a COVID-19 vaccination or whether your vaccination worked. They also do not verify immunity against future infection.
Current US Travel Requirements
As of May 12, 2023, the US no longer requires evidence of COVID-19 immunization for non-U.S. citizens and non-U.S. immigrant flight passengers. On June 12, 2022, the CDC also stopped mandating a negative COVID-19 test for aviation passengers arriving in the United States. This means that, for most visitors, neither a COVID-19 test nor an antibody test result is needed for admission into the United States.
When Antibody Tests Might Be Relevant
Although travel usually does not call for an antibody test, your doctor may advise one if:
You had COVID-19 symptoms in the past but weren't tested.
Having healed from COVID-19, you wish to give plasma.
A rare complication associated with COVID-19, Multisystem Inflammatory Syndrome in Children (MIS-C), presents symptoms in a young child.
Antibody Test Accuracy
Antibody tests are not perfect. False positives—a positive outcome devoid of antibodies—and false negatives—an adverse outcome resulting from antibodies—can also arise. Furthermore, the type of test employed and the time of the test—too soon after infection—influence a test's accuracy.
Testing Procedures
Should your doctor advise an antibody test, they will collect a blood sample—usually by finger prick or blood draw from a vein. Usually, results show up a few days later.
Staying Safe During Travel
Remember that reinfection with COVID-19 is likely even with a positive antibody test. Use advised safety measures, including regular hand washing, keeping current on COVID-19 immunizations, and avoiding close contact with ill people. Examining the particular criteria of your travel destination is also a brilliant idea since certain nations might still impose their COVID-19-related limitations.
| Organization/Source | Antibody Test Requirement for US Entry | COVID-19 Test Requirement for US Entry | Required Test Type | Testing Time Frame | Vaccination Requirement for US Entry | Additional Requirements/Information |
|---|---|---|---|---|---|---|
| United States immigration law | Not applicable | Required for immigrant visa applicants (excluding K visas) | COVID-19 vaccine (some waivers applicable) | From October 1, 2021 | COVID-19 vaccination required for IV applicants (some waivers applicable). K visa applicants are encouraged, but not required, to fulfill vaccination requirements. | Other vaccinations required for immigrant visa applicants. |
| Dinsmore & Shohl LLP | Antibody test results not accepted for proving current infection. Documentation of recovery accepted | Required (as of January 21, 2021) | Viral test (antigen or PCR) | Within 3 days before flight departure | Not required (as of November 2, 2021) | Rule applies to all air travelers 2+, including vaccinated individuals. Rule does not apply to flights from US territories. CDC recommends testing 3-5 days post-arrival and 7 days of home quarantine. |
| Chinese Embassy/Consulates | Antibody test results not accepted | Required for China-bound Passengers | Nucleic Acid RT-PCR Test | Within 3 days before flight's departure | Not required | Recommends direct flights. Health Declaration Forms processed 7 days/week. Apply for certification at least one day before departure. Check with airlines for specific arrangements. |
| Science Advances Study (June 12, 2024) | At-home antibody tests studied as prompt for vaccination | Not applicable | Not applicable | Not applicable | Study examined link between antibody test results and need for booster vaccination. | Study focused on health care workers with prior mRNA vaccines. Negative at-home tests accurately indicated lack of antibodies. Positive tests did not confirm protection. |
| Global Travel Clinics | Offered | Offered (PCR and Antigen) | PCR, Antigen, Antibody | PCR: 8-24 hrsAntigen: Not specifiedAntibody: 48 hours or less | Not required | Services for residents, travelers, and businesses. Travel certificates provided. Notes changing country requirements. |
| Southern California Multi-Specialty Center (SCMSC) | Offered | Offered | Antibody (IgG), PCR | Antibody: Results available through Quest DiagnosticsPCR: Results available through Quest Diagnostics | Not required | Antibody test checks for IgG antibodies (indicating past exposure/recovery). Pre-payment required. Results available through Quest Diagnostics. |
| afar.com | Not applicable (antibody tests not accepted) | Information on various countries | Viral Test (NAAT or Antigen) | Within 1 day of travel to US | Vaccination information for some countries | Provides information about specific countries (UK, Hawaii, various Asian countries, Canada, Australia, New Zealand). |
| Mayo Clinic | Not applicable (antibody tests not accepted) | Recommends adding to travel planning. Mentions potential need for documentation | Viral test (NAAT or antigen) | Within 1 day of travel (for unvaccinated travelers from some destinations) or 3 days of travel (for vaccinated travelers) as of November 2021. Rules may have changed. | Recommends being up-to-date | General advice for travel during the pandemic. Focus on risk reduction strategies: vaccination, masking, distancing, hygiene. Recommends having a COVID-19 kit. |
| U.S. Department of State - STEP | Not applicable | Not applicable (testing requirement ended) | Not applicable | Not applicable | Not applicable | Recommends checking travel advisories. Information about the Smart Traveler Enrollment Program (STEP). |
| Yale Medicine | Not applicable | Recommends testing if symptomatic, regardless of vaccination status. Consider testing 3-5 days after high-risk exposure. | Molecular (PCR), Antigen, ID NOW | PCR: 1-7 days (Yale New Haven Health System: 76% within 24 hrs, 95% within 48 hrs).Antigen: 10-15 min.ID NOW: ~15 min. | Not applicable | Detailed explanation of different test types and their use cases. Advises against replacing nasal with throat swabs in home tests. |
| Mayo Clinic (Daniel C. DeSimone, M.D.) | Explains antibody testing; not for diagnosing current infection, but suggests past infection or vaccination. | Explains diagnostic tests (molecular and antigen) | Molecular (PCR), Antigen, Antibody | Dependent on the type of test and the provider. | Not applicable | Explains antibodies and their function. Mentions convalescent plasma donation. Provides information about accessing diagnostic tests. |
| CDC | Used for surveillance, epidemiology, and diagnosing MIS-C/MIS-A | NAATs, PCR, Antigen, other diagnostic tests | NAAT, PCR, Antigen, Antibody, other | Varies by test | Not applicable | Detailed overview of test types and their uses. Discusses health equity in testing, vaccination's impact on test results, and test monitoring. |
| Passport Health | Offered | Offered (PCR and Antigen) | PCR, Antigen, Antibody | 24-72 hours for antibody tests | Not applicable | Testing available at various locations (listed by state). Corporate testing available. Information on how tests work. |
| Pixel by Labcorp | Offered. Suggests past infection or vaccination. Not for diagnosing active infection. | Offered (Molecular PCR). For individuals with symptoms. | Molecular PCR, Antibody | PCR: 1-2 days after sample received.Antibody: Results available via Labcorp | Patient app. | Not applicable | Provider-collected and self-collected sample options for PCR test. Results available via Labcorp | Patient app. |
| FDA | Provides information about antibody tests; notes limitations for determining current infection, immunity, or vaccine need. | Not applicable | Antibody (Qualitative, Semi-quantitative, Quantitative) | Varies by test and lab. | Not applicable | Explains antibody types (binding, neutralizing). Discusses test types, results, terms (sensitivity, specificity, predictive value). |
| TravelDoc | Offered if required by destination | Offered (RT-PCR and Rapid Antigen) | RT-PCR, Rapid Antigen, Antibody | RT-PCR: 24-36 hoursRapid Antigen: ~15 minutesAntibody: Dependent on lab. | Not applicable | Tests outbound travelers only. No testing for symptomatic individuals. Provides certificates for negative results. Booking and payment instructions. FAQ section. |
| NAFSA | Not applicable | Tracks US visa/entry restrictions related to COVID-19 | Viral Test (NAAT or Antigen) | Within 1 day of departure | Vaccine requirement for nonimmigrant air travelers ended May 11, 2023. | Information about visa services, land border controls, airport regulations, mask mandates. Links to other COVID-19 resources. |
| American Airlines | Documentation of recovery from COVID-19 accepted (as of January 15, 2021) | Required (as of January 15, 2021) | Viral test (NAAT or antigen) | Within 3 calendar days of departure | Not applicable (no longer required) | Requires CDC attestation form. Addresses connecting flights, short trips, recovered travelers. No testing provided by American. Change fee waivers. |
| Voyager Guru | Not applicable | Required within 1 calendar day of departure (as of December 2021) | Viral antigen or PCR | Within 1 calendar day of departure | Required | Discusses at-home proctored tests. Recommends ordering tests early. Provides information on testing locations and what to do if positive. |
| Washington Health Institute | Offered. For individuals suspecting past infection (2-4+ weeks prior). | Offered (Rapid Antigen, RT-PCR) | Rapid Antigen, RT-PCR, Antibody | Rapid Antigen: 15 minutesRT-PCR: 2-5 daysAntibody: 1-3 days | Not applicable | CDC protocols in place. Contactless pre-visit registration. |
| Lonely Planet | Not applicable | Required for air travel (as of November 2021), not required for land border crossings | PCR or antigen (for air travel) | Within 3 days of flying (vaccinated), within 1 day (unvaccinated) | Required for foreign nationals | Exceptions for children under 2, airline crews, federal law enforcement. Addresses recovered travelers and positive test scenarios. |
| U.S. Embassy Santo Domingo | Not applicable | Required (as of April 19, 2021) | Viral test (NAAT or antigen) | Within 3 calendar days of travel | Not applicable | Applies to all air passengers 2+. Alternative: documentation of recovery within 90 days. List of private testing providers available on website. |
| U.S. Embassy Abu Dhabi | Not applicable | Required (as of December 6, 2021) | Viral test (NAAT or antigen) | Within 1 calendar day of departure | Required for nonimmigrant, non-citizen air travelers (effective November 8, 2021). Limited exceptions. | Proof of vaccination required for fully vaccinated travelers. CDC and WHO-approved vaccines accepted. No longer requires National Interest Exception. |
| IGeneX | Offered (IgM) | Offered (RT-PCR) | RT-PCR, IgM Antibody | RT-PCR & IgM: As little as 6 hours (same day available) | Not applicable | Recommends RT-PCR over rapid antigen tests. Highlights varying and changing regulations. Offers same-day testing. |
| Allianz Travel Insurance | Not accepted | Required by some destinations (especially for unvaccinated) as of July 2023 | PCR, rapid molecular or antigen test | 48-72 hours before departure from the US (depending on destination) | Not required for US entry | Interactive map for entry restrictions. Recommends testing if symptomatic, visiting high-risk individuals, or after high-risk exposure. Offers 24-hour Assistance. |
| MHRA | Offered to NHS/care staff, hospital patients, care home residents (also available privately). Not for diagnosis, but for understanding prevalence. | Offered (Virus tests/swab tests, antigen tests). No longer required for international travel. | Virus test (swab test, antigen test, lateral flow), Antibody | Lateral flow antigen: under 30 min. Others: Varies by test and lab | Not required | Details different test types and sample collection. Information on self-testing and regulations. Yellow Card scheme for reporting problems. |
| CityHealth Urgent Care | Not applicable (antibody tests not accepted for entry) | For US and international travel, Hawaii, essential workers, events/venues, personal use, symptoms, exposure. | Molecular PCR, Rapid Molecular, Rapid Antigen, Rapid Return | Molecular PCR: 24-36 hrsRapid Molecular: 2 hrsRapid Antigen & Rapid Return: ~15 min. | Not applicable | Detailed guide for selecting the right test. Testing locations/scheduling tools. Information on test functionality, accuracy, and usage. |
| FDA (Transition Plans for Devices related to COVID-19) | Not applicable | EUA process and transition plans | Multiple (Molecular, Antigen, Serology) | Varies by test | Not applicable | Provides guidance on transitioning medical devices from pandemic policies to normal operations. Lists authorized antigen tests and revisions for viral mutations and serial testing. |
| U.S. Embassy Port of Spain | Not applicable | Required. PCR or Antigen test. | PCR or Antigen | Vaccinated: within 3 calendar daysUnvaccinated: within 1 calendar day (2+ years old), within 3 calendar days (under 2) | Attestation of vaccination status required. | Specific requirements for U.S. citizens, LPRs, and their children. Recommends STEP enrollment and monitoring updates. Contact information provided. |
| CDC (Vaccination Requirements Ended May 12, 2023) | Not applicable | Ended June 12, 2022 | NAAT or Antigen | Within 1 day of departure | Vaccination requirements ended May 12, 2023 | Provides details on the end of vaccination and testing requirements. Lists accepted COVID-19 vaccines. Tables of countries with limited vaccine availability and qualifying vaccine candidates. |
| Advanced Dallas Hospital & Clinics | Offered | Offered (PCR/DNA) | PCR/DNA, Antibody | PCR/DNA: within 72 hoursAntibody: 15 minutes | Not applicable | On-site lab capabilities. Accepts most insurance. Provides PCR test results within 72 hours. Offers risk screening. |
| Nomad Travel | Not accepted for US entry. | Required for entry to the USA | Rapid antigen LFT, PCR, LAMP | Within 1 day before flight departure | Not applicable | Provides tests meeting US entry requirements. LFT results within 2 hours. Quarantine information for vaccinated and unvaccinated travelers. |
| Ichor Blood Services | Not applicable | Required for entry to Canada (PCR)Required for flights to the US (PCR or Antigen) | PCR, Antigen | 72 hours prior to travel (both directions),Antigen (to US): less than 30 min.PCR (from US): within 48 hours. | Required for land/ferry travel to US, not required for flights | Offers rapid PCR and antigen tests. Virtual testing available for return to Canada. Information about land/marine travel requirements. |
