*4.1. Post-TB Treatment Functional Evaluation*

A baseline examination with functional evaluation can be performed safely when the patient is smear and culture negative (on at least two samples two weeks apart) and is undergoing effective treatment; otherwise, infection control measures are necessary [13]. As the patient might need a different approach when resting and when making exercise (e.g., walking), a careful evaluation should be ideally performed both at rest and under exercise conditions [43,44].

At rest, spirometry with response to the bronchodilator, diffusing capacity of the lung for carbon monoxide (DLCO), arterial blood gases analysis are recommended to study lung mechanics, complemented by plethysmography at the initial evaluation (if feasible) (Figure 1) [43].

Spirometry is the most widely accepted test to assess lung function impairment. It can be conducted with a simple spirometer, which costs a minimum of 150\$ and can be used at point-of-care or with a sophisticated apparatus which includes plethysmography (which is able to diagnose lung restriction and 'air trapping' by measuring the Residual Volume (RV)). The core parameters evaluated by spirometry are forced expiratory volume (FEV)1 (low FEV1 indicates airflow obstruction), FVC (Forced Vital Capacity) and their ratio (FEV1/FVC) [43]. *DLCO* describes the status of gas exchanges at the pulmonary level, which can be hampered even in the presence of normal spirometry and plethysmography.

Under exercise conditions it is useful to have the patient undergo the 6-min walking test (6MWT) or the cardiopulmonary exercise test (CPET) which provides additional information on the physiological reserve (and, indirectly on QoL) [43,44]. The *6MWT* measures the distance covered (in metres) in 6 min. It can be done in any setting, is cheap and easy to interpret: it correlates with QoL and improves after rehabilitation [43–45]. *CPET* is a more sophisticated, expensive, and technology-dependent tool which cannot be performed in all centres. It provides information on the exercise capacity-limiting determinants (respiratory: mechanical or as exchange-related; muscular; and cardio-vascular).

**Figure 1.** Interpreting spirometry. **Legend**: FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; FEV1/FVC ratio: the percentage of the FVC expired in one second; DLCO: diffusing capacity of the lung for carbon monoxide; TLC: total lung capacity.

Different tools exist to evaluate QoL, including generic questionnaires (e.g., 36-item Short Form (SF) health survey or SF-36 and its shortened version with 12 questions, the SF-12) or specific tools as the SGRQ (St. Georges's Respiratory Questionnaire) specifically investigating QoL in chronic respiratory diseases (Table 2).







HRQoL:https://www.optum.com/solutions/life-sciences/answerresearch/patient-insights/sf-health-surveys.html; # Details on scoring are included in manuals available from The WHOQOL Group: https://www.who.int/healthinfo/survey/whoqolqualityoflife/en/index2.html.
