Quality Assessment of Dried Blood Spots from Patients With Tuberculosis from 4 Countries.

BACKGROUND: Dried blood spot (DBS) sampling is a blood collection tool that uses a finger prick to obtain a blood drop on a DBS card. It can be used for therapeutic drug monitoring, a method that uses blood drug concentrations to optimize individual treatment. DBS sampling is believed to be a simpler way of blood collection compared with venous sampling. The aim of this study was to evaluate the quality of DBSs from patients with tuberculosis all around the world based on quality indicators in a structured assessment procedure. METHODS: Total 464 DBS cards were obtained from 4 countries: Bangladesh, Belarus, Indonesia, and Paraguay. The quality of the DBS cards was assessed using a checklist consisting of 19 questions divided into 4 categories: the integrity of the DBS materials, appropriate drying time, blood volume, and blood spot collection. RESULTS: After examination, 859 of 1856 (46%) blood spots did not comply with present quality criteria. In 625 cases (34%), this was due to incorrect blood spot collection. The DBS cards from Bangladesh, Indonesia, and Paraguay seemed to be affected by air humidity, causing the blood spots not to dry appropriately. CONCLUSIONS: New tools to help obtain blood spots of sufficient quality are necessary and environmental specific recommendations to determine plasma concentration correctly. In addition, 3% of the DBS cards were rejected because the integrity of the materials suggesting that the quality of plastic ziplock bags currently used to protect the DBS cards against contamination and humidity may not be sufficient.

CYP2E1 polymorphism, acetylator profiles and drug-induced liver injury incidence of Indonesian tuberculosis patients.

OBJECTIVE: A polymorphism of CYP2E1 may be directly associated with the development of INH hepatotoxicity. We conducted this study to evaluate the association between polymorphisms of CYP2E1, Isoniazid (INH) concentration and the acetylator status of INH in cases of Indonesian tuberculosis patients with drug-induced liver disease (DILI). METHODS: We conducted our study with a cohort design consisting of 55 Indonesian adult tuberculosis (TB) patients. Acetylating phenotypes were studied in using the metabolic ratio of plasma AcHZ/HZ. DILI was defined using CTCAV version 4.0. The allelic and genotypic frequency distributions of CYP2E1 rs 3813867 were studied using the polymerase chain reaction - amplification refractory mutation system (ARMS) methodology. RESULTS: Patients with an INH concentration of more than 7µg/mL showed a higher risk of developing DILI when compared with patients who showed a therapeutic range of 3-6µg/mL INH (OR: 1.3, 95% CI: 0.2-8.2). Slow acetylators had a higher incidence of DILI when compared with rapid acetylators (OR: 4.6, 95% CI: 1.3-15.9). Meanwhile, subjects with GC had a higher risk of DILI incidence (OR: 4.3, 95% CI: 0.8-24.4). CONCLUSION: Our study shows that polymorphisms of CYP2E1 and slow acetylator may have role in the DILI incidence.