Table 2—

Base-case estimates and ranges used in cost-minimisation analysis

Base-caseRangeSource
External costs EUR
 Tuberculin dose (cTub)7.51.5–15Pharmore# price list
 QFT-G test result (labour and QFT tubes; cLab)4020–80Laboratory provider
Outcome: proportion of contacts suspected of having TB disease %10–215–18
Public health service costs EUR
 Reading and registering TST result (doctor, 8 min; cRead)4.06Observed
 Consulting contacts without TB disease (doctor, 25 min; cCons)24Observed
 Administering TST (MTA, 7 min; cAdm)7.68Observed
 Sampling blood for QFT-G (MTA, 7 min; cAdm)7.68Observed
 Read TST (cTST (cRT23+cAdm+cRead))19.2413.24–26.74+Calculated
 Unread TST (cTSTm (cRT23+cAdm))15.18Calculated
 QFT-G test (cQFT (cLab+cAdm))47.6827.68–87.68§
 Chest radiography (cCXR)74.329.38ƒCalculated
 Total cost of QFT-G screening (tcQFT (cQFT+cCXR+cCons))##Calculated
 Total cost of TST screening (tcTST (cTST+cCXR+cCons))##Calculated
 Managing diagnostics for suspected contacts (doctor, 40 min; cSusp)38.4Calculated
 Total cost of TST screening per contact suspected of having TB disease (tcTSTs (cTST+cCXR +cSusp))##Calculated
 Total cost of QFT-G screening per contact suspected of having TB disease (tcQFTs (cQFT+cCXR +cSusp))##Calculated
Test result probabilities
 Proportion of TST-positive contacts (pTST)0.44Study data¶¶
 Proportion of QFT-G-positive contacts (QFT)0.1Study data¶¶
 Proportion of QFT-G-positive contacts among TST-positive contacts (QFTt)0.204Study data¶¶
 Proportion of BCG-vaccinated contacts among TST-positive contacts (ppBCG)0.804Study data¶¶
 Proportion of QFT-G-positive contacts among BCG-vaccinated contacts (pQFTb)0.13Study data¶¶
 Reading TST result (pRead)0.952Observed
 Opting for INH chemoprevention (pPrev)0.50–1.0Assumption
 Evidence of active TB per radiographic examination (pTB)0.00330–0.0066Weighted++
  • Unless otherwise specified, costs are per test/procedure; total costs are per contact. EUR: Euro; QFT-G: QuantiFERON-TB Gold; TB: tuberculosis; TST: tuberculin skin test; MTA: medical technical assistant; RT 23: purified protein derivative of tuberculin RT 23 (2 TU·0.1 mL-1) from the Danish Statens Serum Institute; BCG: bacille Calmette–Guérin; INH: isoniazid. #: Ibbenbüren, Germany; : Labor A. von Froreich, C. Schmidt & Partner, Hamburg, Germany (as per March 1, 2005); +: varies with cost of tuberculin dose; §: varies with cost of QFT-G tube and labour; ƒ: lower limit: cost of referral to radiological practice (using a factor of 1.8 to determine final cost (see Sensitivity analysis section)); ##: depends on number of chest radiographic examinations, contacts without radiological evidence of active TB receive three examinations, suspected contacts drop out of follow-up by the public health service; ¶¶: see table 1; ++: from base-case estimate: probability of a suspected TB result in the series of three chest radiographic examinations is 1%, this is assumed to be equally distributed between the individual examinations.