Operational Handbooks

Web annex 1

Clinical outcomes and pharmacokinetics of first-line drugs (rifampicin, isoniazid, ethambutol and pyrazinamide) in children (aged <18 years) treated for drug-susceptible tuberculosis: systematic review and meta-analysis.
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^{DS-TB: drug-susceptible TB; FDC: fixed-dose combination; TB: tuberculosis.}

Effective communication skills are described in Section 4.2. These need to be practised by health-care providers before they can share the information outlined above as part of health education and counselling.

1. Factual information about TB as a disease and its treatment

Information about TB and its treatment should be explained to the patient. This includes:

To date, the criteria for a positive TBST have been established by the manufacturers. These criteria are based on clinical data in relatively small numbers of patients. In addition, all of the studies to date evaluating accuracy of these tests have used cross-sectional designs. Data from prospective observational or experimental studies may result in modification of these criteria in the future.

Table 3.2. Criteria for a positive TBST

The active ingredient in C-TST (formerly known as the ESAT6-CFP10 test, Anhui Zhifei Longcom, China) is an ESAT-6–CFP-10 fusion recombinant protein expressed in genetically modified E. coli. Each test dose of 0.1 mL contains 5 U of recombinant M. tuberculosis fusion protein, and auxiliary ingredients – disodium hydrogen phosphate, potassium dihydrogen phosphate, sodium chloride, phenol and polysorbate 80 (41).

Fig. 3.3. C-TST vials

Diaskintest (Generium, Russian Federation) is a recombinant protein produced by genetically modified culture of Escherichia coli BL21 (DE3)/pCFP-ESAT, diluted with sterile isotonic phosphate buffer solution, with a preservative (phenol). One dose (0.1 mL) of the product contains 0.2 μg of CFP-10–ESAT-6 recombinant protein, and excipients – disodium phosphate dihydrate, sodium chloride, potassium dihydrogen phosphate, polysorbate 80, phenol and water for injection (40).

Fig. 3.2. Diaskintest package and vial

Cy-Tb (formerly known as the C-Tb test, Serum Institute of India) contains a 1:1 ratio of two recombinant proteins of ESAT-6 and CFP-10 was previously produced by genetically modified Lactobacillus lactis, by Statens Serum Institute (Denmark). One single test dose of 0.1 mL contains 0.05 μg of rdESAT-6 and 0.05 μg of rCFP-10.

Fig. 3.1. Vial of Cy-Tb

The sensitivity of TST based on different size criteria of induration was established among people who had been treated for and had recovered from microbiologically confirmed TB (34). Of these, 98% had a reaction of 5 mm or more to TST, 90% had a reaction of 10 mm or more but only 60% had a reaction of 15 mm or more. On the other hand, reactions to TST due to BCG or nontuberculous mycobacteria are usually smaller than TST reactions due to true infection with M. tuberculosis (11, 12).