Quest Rabies Titer Test: What It Measures and Who Needs One

A Quest rabies titer test — listed in the Quest Diagnostics Test Directory as the Rabies Vaccine Response End Point Titer (test code 5789) or the Rabies Antibody Screen RFFIT (test code 91326) — is a blood test that measures rabies virus neutralizing antibodies (RVNA) in a person who has already received rabies vaccination. It uses the Rapid Fluorescent Focus Inhibition Test (RFFIT) method, and a result at or above 0.5 IU/mL is considered protective under World Health Organization (WHO) and CDC Advisory Committee on Immunization Practices (ACIP) guidance. It is a human occupational-health test — not the pet travel titer test that airlines and countries require for dogs and cats.

What Is the Quest Rabies Titer Test?

The Quest Diagnostics Test Directory carries two rabies serology entries built on the same underlying method: test 5789, the Rabies Vaccine Response End Point Titer, and test 91326, the Rabies Antibody Screen RFFIT. Both rely on the RFFIT, a serum-neutralization assay that mixes diluted serum with a fixed dose of live rabies virus and measures how much virus the antibodies in the sample can neutralize before it can infect laboratory cells.

RFFIT-based testing is designated for both human and veterinary use, according to the Kansas State Veterinary Diagnostic Laboratory (KSVDL), one of the highest-volume rabies serology centers in the world. In practice, the Quest order codes are used almost exclusively for people: veterinarians, veterinary technicians, animal control officers, wildlife biologists, rabies laboratory staff, and other workers whose jobs put them at recurring risk of rabies exposure.

Who Actually Needs a Rabies Titer Check?

The Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices (ACIP) updated its rabies pre-exposure prophylaxis (PrEP) recommendations on September 5, 2024. Under that guidance, immunocompetent adults age 18 and older who complete the standard 2-dose PrEP series (given on days 0 and 7) do not need a routine titer check afterward. The picture changes for two groups:

• Immunocompromised individuals must have a titer drawn no sooner than one week after finishing the PrEP series (ideally 2–3 weeks after), and it must reach ≥0.5 IU/mL or additional vaccine doses and repeat testing are required, per ACIP.
• People with sustained rabies exposure risk (ACIP's "risk category 3" — for example, rabies researchers and diagnostic lab workers) can choose a one-time titer check between years 1 and 3 after PrEP, with a booster dose if the result falls below 0.5 IU/mL, or take a booster on that same 1–3 year schedule instead of testing.

This is the population that typically orders a Quest rabies titer test — not pet owners.

What Antibody Level Counts as "Protective"?

Both the WHO and ACIP set the protective threshold for rabies virus neutralizing antibodies at 0.5 IU/mL or higher. Below that level, current guidance calls for a booster dose, particularly for anyone at continued occupational or recreational risk of rabies exposure (for example, cavers who may encounter bats). Results are typically reported by KSVDL and similar reference labs as a numerical IU/mL value rather than a simple pass/fail.

Quest Rabies Titer (RFFIT) vs. Pet Travel Titer (FAVN)

This is the point where the "quest rabies titer" search term most often causes confusion. Quest Diagnostics' RFFIT-based tests and the FAVN test required for international pet travel both measure rabies antibodies, but they serve different species, different purposes, and different regulatory systems. KSVDL's own rabies titer comparison page draws a direct line between the two:

The takeaway: if you need a rabies titer to move a dog or cat across a border, ordering the Quest RFFIT test is the wrong test. Pet travel titers must go through a lab accredited to run FAVN for export, submitted by a licensed veterinarian.

How the RFFIT Test Works

1. A blood sample is drawn and the serum is separated.
2. The serum is diluted in a fivefold series (roughly 1 part serum to 4 parts diluent), with each subsequent dilution containing less serum.
3. Each dilution is mixed with a standard, known quantity of live rabies virus and incubated.
4. If rabies virus neutralizing antibodies are present, they bind to and neutralize the virus in that dilution.
5. Laboratory cells are added; any virus that was not neutralized infects the cells, which is then measured under fluorescence.
6. The lab calculates the antibody concentration in IU/mL from the highest dilution that still shows neutralization.

Cost and Turnaround Time

Prices and processing times vary by accredited laboratory and change over time, so treat the figures below as illustrative rather than fixed. According to RabiesAware.org's lab comparison, as of this writing:

• Kansas State University (KSVDL): approximately $84 per FAVN sample, with a 10–14 calendar day turnaround and no expedited option.
• University of Missouri: approximately $79 per sample for export FAVN testing, or $58 for non-export rabies antibody testing, with results in about 7–10 business days.
• Auburn University: FAVN only (no longer offers RFFIT for pet travel), with a current turnaround of roughly 4–5 weeks and no expedited samples.

Note the disagreement even within KSVDL's own pages: its rabies titer comparison chart lists a 3–4 week turnaround for both RFFIT and FAVN, while its dedicated FAVN test page and a June 2023 Kansas State University news release describing the lab's online FAVN submission portal cite a faster 10–14 calendar days. Always confirm current pricing and turnaround directly with the lab you plan to use, especially if a travel deadline is involved.

What Happens If Your Titer Is Low?

For people, ACIP guidance calls for a booster vaccine dose if a titer comes back below 0.5 IU/mL, followed by repeat testing in immunocompromised individuals to confirm an adequate response. For pets, a FAVN result below the threshold required by the destination country generally means the animal is not yet eligible to travel and may need a booster vaccination followed by a new waiting period — commonly around 21–30 days after vaccination — before blood is redrawn, per KSVDL's submission guidelines.

Rabies Titer Testing in Context

The World Health Organization estimates roughly 59,000 people die of rabies globally each year, with dog bites and scratches responsible for about 99% of human cases — a burden it says is preventable primarily through dog vaccination. That global scale is part of why occupational rabies titer testing exists at all: people who work around animals at elevated exposure risk need a way to confirm their vaccine-induced immunity is holding, and a Quest rabies titer test is one route to get that confirmation through a standard blood draw at a commercial lab.

Where Vaccination Records Fit In

Whether a titer is for a person's occupational health file or a pet's travel paperwork, the underlying problem is the same: proving a vaccination happened and knowing when the next check or booster is due. Paper vaccination cards and clinic-specific records are easy to lose — a livestock version of that problem played out during the August 2025 floods in Pakistan, when paper ear tags washed away and farmers struggled to prove which animals were theirs and what care those animals had already received. Animal Passport was used in that flood response to give livestock a phone-captured, muzzle-biometric digital record binding an animal to its owner, breed, estimated age, and vaccination history, so identity and care history survived even when physical tags did not. That kind of digital record does not replace a lab-run titer test or a veterinarian's export certification, but it does make it easier to see, at a glance, when a vaccination was given and when a booster or recheck is coming due. For more on how digital identity and vaccination tracking works for animals, see the Animal Passport blog.

Frequently Asked Questions About the Quest Rabies Titer Test

What is a Quest rabies titer test?

It is a blood test in the Quest Diagnostics Test Directory (test codes 5789 and 91326) that measures rabies virus neutralizing antibodies using the RFFIT method, typically ordered for people who have received rabies vaccination and need to confirm protective immunity.

Is the Quest rabies titer test the same as the pet travel titer test?

No. Quest's RFFIT-based test is a human occupational-health test. Pet travel to rabies-free countries or regions requires the FAVN test, which is run only through accredited veterinary laboratories and submitted by a veterinarian.

What antibody level is considered protective against rabies?

A result of 0.5 IU/mL or higher is the protective threshold used by both the World Health Organization and the CDC's Advisory Committee on Immunization Practices.

Who needs to get a rabies titer test?

People with ongoing occupational or recreational rabies exposure risk — veterinarians, vet techs, animal control officers, wildlife biologists, and rabies lab workers — along with immunocompromised individuals after completing pre-exposure vaccination, per current ACIP guidance.

Do I need a titer check after getting the rabies pre-exposure vaccine series?

Under ACIP's September 2024 update, most immunocompetent adults do not need a routine titer after the 2-dose series; immunocompromised people and those in sustained-risk categories still have titer or booster requirements.

How much does a rabies titer test cost and how long does it take?

Cost and turnaround vary by lab: examples include roughly $84 for a FAVN sample at Kansas State University (10–14 days) and $58–$79 at the University of Missouri (7–10 business days). Confirm current figures with the lab directly before relying on them for travel.

Can Quest Diagnostics test my dog's or cat's rabies titer for travel?

No. Quest Diagnostics' listed rabies titer tests are designed for human samples. Pet export titers must be run as a FAVN test through an accredited veterinary reference laboratory, submitted by a veterinarian.

What happens if my rabies titer result is below 0.5 IU/mL?

For people, current guidance recommends a booster vaccine dose and, for immunocompromised individuals, repeat testing to confirm the booster worked. For pets, a low FAVN result generally means the animal isn't yet cleared to travel and may need a booster plus a new waiting period before retesting.

As of September 2026, the most recent ACIP update on rabies PrEP titers dates to September 5, 2024, and no subsequent CDC revision to the 0.5 IU/mL threshold has been published. Always verify current lab pricing, turnaround, and destination-country import rules before scheduling a titer test tied to a travel deadline.