Latent tuberculosis infection: contact, before immunosuppressant, at-risk populations

• Without delay: consultation and chest X-ray (looking for active tuberculosis), in liaison with the CLAT (TB control centre) coordinating the investigation.

At least 8 weeks after the last contact

• IGRA test (QuantiFERON or T-SPOT.TB) — adult over 15 years, contact investigation around a caseif neededAdult (over 15) contact of a tuberculosis case: a single immunological test, tuberculin skin test (IDR) or IGRA, at least 8 weeks after the last contact ^[2]; IGRA covered in contact investigation around a case in adults ^[3].
• Tuberculin skin test (child aged 5 to 15 years, or optional in adults)if neededChild aged 5 and over: a single test (IDR or IGRA) 8 to 12 weeks after the last contact ^[2]; IGRA is not covered in contact investigation around a case in children aged 15 or under ^[3].

• Within 2 weeks of the diagnosis of the index case: clinical examination, chest X-ray (frontal, with lateral view at the slightest doubt) and tuberculin skin test, in liaison with the CLAT (TB control centre) and the paediatrician. Abnormal X-ray: immediate contact with the reference paediatric department.

Tests

• Tuberculin skin test (Tubertest)
• IGRA test instead of the tuberculin skin test (possible since 2019)if neededThe HCSP (High Council for Public Health) accepts replacing IDR with IGRA in children aged 0 to 5 exposed to pulmonary tuberculosis ^[4].

3 months after the last contact (if the first assessment is negative)

• Tuberculin skin test (2nd assessment)if neededNo initial argument for latent TB infection (LTBI): second assessment 3 months after the last contact ^[2].

Laboratory tests

• IGRA test (before anti-TNF or anti-JAK, or discovery of HIV infection)if neededBefore any anti-TNF (IGRA preferred) and in any person whose HIV infection has just been discovered and who is about to start antiretroviral treatment (IGRA if CD4 > 50/mm3) ^[4]; covered, as is testing before an anti-JAK ^[3].
• IGRA test (organ transplant candidate, advanced renal failure or dialysis)if neededRoutine LTBI screening recommended, by IGRA or IDR, before solid organ transplantation and in advanced kidney failure or dialysis patients ^[4].
• Second IGRA test using a different technique (indeterminate or negative result in an immunocompromised patient)if neededIndeterminate IGRA: repeat IGRA with another technique ^[4]; in immunocompromised patients (HIV, anti-TNF, anti-JAK), a check with another technique may be justified after a negative or indeterminate result ^[3].

Laboratory tests (depending on the situation)

• IGRA test (migrant child under 15 years from a country with incidence > 40/100 000)if neededLTBI screening in young migrants from a country with an incidence > 40/100 000, as early as possible after arrival, unnecessary 5 years later ^[4]; IGRA covered before age 15 ^[3].
• IGRA test (at-risk migrant aged 15 to 40 years, expatriate, healthcare worker at recruitment)if neededMigrant aged 15 to 18; migrant aged 18 to 40 from a country with an incidence > 100/100 000, arrived less than 5 years ago and immunocompromised, living with children, or working in a childcare or health care setting; expatriate for more than 6 months in a country with an incidence > 100/100 000, case by case, at least 8 weeks after return; health worker or health student on recruitment (IGRA preferred if BCG) ^[4].

Before treatment

• FBCif neededPre-treatment tests are mandatory in chronic liver disease, excess alcohol, HIV infection, immunosuppression, pregnancy or post-partum (3 months), treatment interfering with rifampicin, or after age 35; not routine in children ^[4]. Content (not detailed by the HCSP 2019): blood count, transaminases, alkaline phosphatase, serum creatinine according to the HCSP 2013, which recommended it in every adult ^[2].
• ASTif neededPre-treatment tests are mandatory in chronic liver disease, excess alcohol, HIV infection, immunosuppression, pregnancy or post-partum (3 months), treatment interfering with rifampicin, or after age 35; not routine in children ^[4]. Content (not detailed by the HCSP 2019): blood count, transaminases, alkaline phosphatase, serum creatinine according to the HCSP 2013, which recommended it in every adult ^[2].
• ALTif neededPre-treatment tests are mandatory in chronic liver disease, excess alcohol, HIV infection, immunosuppression, pregnancy or post-partum (3 months), treatment interfering with rifampicin, or after age 35; not routine in children ^[4]. Content (not detailed by the HCSP 2019): blood count, transaminases, alkaline phosphatase, serum creatinine according to the HCSP 2013, which recommended it in every adult ^[2].
• Alkaline phosphataseif neededPre-treatment tests are mandatory in chronic liver disease, excess alcohol, HIV infection, immunosuppression, pregnancy or post-partum (3 months), treatment interfering with rifampicin, or after age 35; not routine in children ^[4]. Content (not detailed by the HCSP 2019): blood count, transaminases, alkaline phosphatase, serum creatinine according to the HCSP 2013, which recommended it in every adult ^[2].
• Serum creatinineif neededPre-treatment tests are mandatory in chronic liver disease, excess alcohol, HIV infection, immunosuppression, pregnancy or post-partum (3 months), treatment interfering with rifampicin, or after age 35; not routine in children ^[4]. Content (not detailed by the HCSP 2019): blood count, transaminases, alkaline phosphatase, serum creatinine according to the HCSP 2013, which recommended it in every adult ^[2].
• Hepatitis B serologyif neededHepatitis B and C serology may be offered to adults from high-endemicity countries before treatment ^[2].
• Hepatitis C serology (person from a high-endemicity country)if neededHepatitis B and C serology may be offered to adults from high-endemicity countries before treatment ^[2].
• HIV serology (if serological status unknown)if needednon-French guidelineProposed by NICE (United Kingdom) before any treatment of latent tuberculosis infection ^[5]; HIV is listed there among the situations at risk of progression to active tuberculosis and guides the choice of regimen, because of interactions with rifamycins ^[5]. The 2019 HCSP report does not provide for it in the pre-treatment tests, which it makes mandatory in known HIV infection ^[4].

At day 15, day 30, then every month during treatment

• ASTif neededTransaminases on D15, D30 then every month in at-risk subjects (over 65, other hepatotoxic drugs, pre-existing liver disease) ^[2]; periodic laboratory monitoring if the initial tests are abnormal ^[4].
• ALT (patient at hepatic risk or abnormal baseline results)if neededTransaminases on D15, D30 then every month in at-risk subjects (over 65, other hepatotoxic drugs, pre-existing liver disease) ^[2]; periodic laboratory monitoring if the initial tests are abnormal ^[4].