So the patient can in fact have his or her medication with food as long as the meal does not contain fat or oils (e.g., a cup of black coffee or toast with jam and no butter). Taking the medicines with food also helps ease the nausea that many patients feel when taking the medicines on an empty stomach. The effect of food on the absorption of INH is not clear: two studies have shown reduced absorption with food but one study showed no difference. There is a small effect of food on the absorption of PZA and of EMB that is probably not clinically important.It is possible to test urine for isoniazid and rifampicin levels to check for compliance. The interpretation of urine analysis is based on the fact that isoniazid has a longer half-life than rifampicin:
urine positive for isoniazid and rifampicin – patient probably fully compliant
urine positive for isoniazid only – patient has taken his medication in the last few days preceding the clinic appointment, but had not yet taken a dose that day. urine positive for rifampicin only – patient has omitted to take his medication the preceding few days, but did take it just before coming to clinic. urine negative for both isoniazid and rifampicin – patient has not taken either medicine for a number of daysIn countries where doctors are unable to compel patients to take their treatment (e.g., the UK), some say that urine testing only results in unhelpful confrontations with patients and does not help increase compliance.
Located in India and Cambodia, Operation ASHA focuses on the development of "e-Compliance," which is a verification and SMS text messaging system where patients can use their fingerprints to access their medical records and be reminded daily via text when to take their medication. According to Operation ASHA, the e-Compliance treatment successive rate is 85%. Treatment failure
Patients who fail treatment must be distinguished from patients who relapse. Patients who responded to treatment and appeared to be cured after completing a course of TB treatment are not classed as treatment failures, but as relapses and are discussed in a separate section below. Patients are said to have failed treatment if they

fail to respond to treatment (cough and sputum production persisting throughout the whole of treatment), or
only experience a transient response to treatment (the patient gets better at first, but then get worse again, all the while on treatment).It is very uncommon for patients not to respond to TB treatment at all (even transiently), because this implies resistance at base-line to all of the drugs in the regimen. Patients who fail to get any response at all while on treatment should first of all be questioned very closely about whether or not they have been taking their medicines, and perhaps even be admitted to hospital to be observed taking their treatment. Blood or urine samples may be taken to check for malabsorption of TB drugs.