What lab test is required before getting a tetanus, diphtheria, and pertussis (Tdap) vaccine?

No Lab Test Required Before Tdap Vaccination

No laboratory testing is required before administering the tetanus, diphtheria, and pertussis (Tdap) vaccine. Tdap is given based on vaccination history and timing, not laboratory results.

Standard Vaccination Approach

The recommended approach for Tdap administration relies entirely on clinical history, not serologic testing 1:

• Routine vaccination: Adolescents aged 11-12 years receive a single Tdap dose, followed by Td boosters every 10 years throughout adulthood 2, 3
• Adults who never received Tdap: Administer one dose of Tdap regardless of interval since last tetanus-containing vaccine, then continue with Td every 10 years 1, 2
• Pregnancy: One dose of Tdap during each pregnancy between 27-36 weeks gestation, regardless of prior vaccination history 2, 4

When Serologic Testing Is an Alternative (Not Standard)

Laboratory testing is mentioned only as an alternative approach in very specific circumstances, not as a routine requirement 1:

• For persons vaccinated outside the U.S. with no vaccination records: Serologic testing for specific IgG antibody to tetanus and diphtheria toxins can be performed to avoid unnecessary vaccination 1
• If antitetanus and antidiphtheria levels are each ≥0.1 IU/mL: Previous vaccination is presumed, and only a single Tdap dose is indicated 1

This alternative approach is explicitly listed as optional, not recommended, in ACIP guidelines 1.

Clinical Algorithm for Tdap Administration

Step 1: Determine vaccination history

• If documented complete primary series (3+ doses) and last dose was ≥10 years ago → Give Tdap now 2, 3
• If never received Tdap → Give Tdap now regardless of interval since last Td 1, 2
• If unknown/incomplete history → Consider patient unvaccinated and start/complete 3-dose series with one dose being Tdap 1

Step 2: For wound management

• Clean, minor wounds: Give tetanus-containing vaccine only if >10 years since last dose 2, 3
• Contaminated/tetanus-prone wounds: Give tetanus-containing vaccine if >5 years since last dose, plus TIG if primary series incomplete 1, 2

Step 3: No lab work needed

• Proceed directly to vaccination based on history alone 1

Critical Pitfalls to Avoid

• Do not order tetanus antibody titers routinely: This delays vaccination and is not part of standard practice 1, 2
• Do not give tetanus boosters more frequently than every 10 years for routine immunization: This increases risk of Arthus-type hypersensitivity reactions 1, 2, 3
• Do not confuse the alternative approach with the recommended approach: Serologic testing is only for special circumstances like unknown vaccination history in immigrants, not routine practice 1