Economic Impact

The T-SPOT.TB test is a cost effective solution for TB screening when compared to the significant costs associated with the tuberculin skin test (TST).  Total costs for the tuberculin skin test are often believed to be lower than the actual cost.  According to a published study by Lambert et al., the total cost of a tuberculin skin test per healthcare worker tested ranged from $41.00USD to $362.00USD.3

Some of the tuberculin skin test’s less obvious costs include:


  • Two visits are required, one for administration of the PPD and the second for interpretation of the test result.
  • Subjectivity of test administration and interpretation of results


  • Training and retraining in proper test inoculation and interpretation
  • Chasing healthcare workers to return for the second visit
  • Two-step TST (where carried out) for new employees requires a total of four visits


  • The TST cross-reacts with the BCG vaccine resulting in false-positive results
  • TST results are affected by immunosuppression resulting in false-negative results.4


The T-SPOT.TB test addresses the sources of these costs associated with the TST:

  • Single blood test, only one visit required
  • The T-SPOT.TB test results are not affected by immunosuppression or BCG vaccine5
  • Comprehensive TB Testing Coverage: the ability to test all patients and HCWs with the T-SPOT.TB test

The table below highlights the most signficant cost savings:



Annual Healthcare Worker (HCW) Screening1,2    One Visit

  • HCW time
  • Phlebotomist time




Two Visits

  • HCW time initial visit
  • Nurse labor for administration
  • HCW time for return visit
  • Nurse labor for interpretation


New HCW screening One Visit

  • HCW time
  • Phelbotomist time
Four Visits
(Two-step testing)*1st Test:

  • HCW time initial visit
  • Nurse labor for administration
  • HCW time for return visit
  • Nurse labor for interpretation

2nd Test:

  • HCW time initial visit
  • Nurse labor for administration
  • HCW time for return visit
  • Nurse labor for interpretation

*where applicable

Patient testing One Visit

  • Patient time
  • Phlebotomist time
Two Visits

  • Patient time initital visit
  • Nurse labor for return visit
  • Patient time for return visit
  • Nurse labor for interpretation
BCG vaccinated patient or HCW Results are not affected by BCG vaccine Cross-reacts with BCG vaccine.Cost of false positive result:

  • Chest x-ray
  • Unnecessary treatment and follow-up


Immunosuppressed patient or HCW Results are not affected by immunosuppression Results are affected by immunosuppression.Cost of false negative result:

  • Missed cases convert to TB disease leading to morbidity and higher costs of treating disease
Subjects miss clinics Only one visit required Two visits are required.  Up to one third of subjects do not return for test interpretation
Un-used reagents Only use sufficient reagents for each test PPD must be used within one day of opening.  Un-used PPD is discarded


1Wrighton-Smith P, et al., Screening Health Care Workers With Interferon-γ Release Assay Versus Tuberculin Skin Test. JOEM Volume 54, Number 7, July 2012

2Eralp MN, et al., Screening of healthcare workers for tuberculosis: development and validation of a new health economic model to inform practice. BMJ Open. 2012 Mar 1;2(2)

31Lambert L et al., Costs of Implementing and Maintaing a Tuberculin Skin Test Program in Hospitals and Health Departments.  Inf Con and Hosp Epidm  2003:  814-821

.4Lee J et al., Comparison of two commercial interferon-gamma assays for diagnosing Mycobacterium tuberculosis infection.  Eur Respir J 2006:  28:  24-30.

5T-SPOT.TB Pivotal Clinical Study.  T-SPOT.TB results were not associated with immunocompromised status.  T-SPOT.TB Package Insert.

To see a summary of key clinical studies, here.