Intra-individual effects of food upon the pharmacokinetics of rifampicin and isoniazid.

Background: Poor response to TB therapy might be attributable to subtherapeutic levels in drug-compliant patients. Pharmacokinetic parameters can be affected by comorbidities or the interaction of drugs with food. Objectives: This study aimed to determine the effect of food intake upon pharmacokinetics of rifampicin and isoniazid in a Peruvian population with TB. Methods: Rifampicin and isoniazid levels were analysed at 2, 4 and 6 h after drug intake in both fasting and non-fasting states using LC-MS methods. Results: Sixty patients participated in the study. The median rifampicin Cmax and AUC0-6 were higher during fasting than non-fasting: 7.02 versus 6.59 mg/L (P = 0.054) and 28.64 versus 24.31 mg·h/L (P = 0.002). There was a statistically significant delay overall of non-fasting Tmax compared with the fasting state Tmax (P = 0.005). In the multivariate analysis, besides the effect of fasting, Cmax for females was 20% higher than for males (P = 0.03). Concerning isoniazid, there were significant differences in the Cmax during non-fasting (median = 3.51 mg/L) compared with fasting (4.54 mg/L). The isoniazid dose received had an effect upon the isoniazid levels (1.26, P = 0.038). In the multivariate analysis, isoniazid exposure during fasting was found to be 14% higher than during non-fasting (CI = 1.02-1.28, P < 0.001). Neither radiological extent of the disease nor consumption of food with drug intake nor pharmacokinetics of rifampicin or isoniazid was associated with a poorer treatment outcome. Conclusions: Rifampicin in particular and isoniazid pharmacokinetics were significantly affected by the intake of the drug with food between and within individuals.

Multidrug-Resistant Tuberculosis Treatment Outcomes in Relation to Treatment and Initial Versus Acquired Second-Line Drug Resistance.

BACKGROUND: Resistance to second-line drugs develops during treatment of multidrug-resistant (MDR) tuberculosis, but the impact on treatment outcome has not been determined. METHODS: Patients with MDR tuberculosis starting second-line drug treatment were enrolled in a prospective cohort study. Sputum cultures were analyzed at a central reference laboratory. We compared subjects with successful and poor treatment outcomes in terms of (1) initial and acquired resistance to fluoroquinolones and second-line injectable drugs (SLIs) and (2) treatment regimens. RESULTS: Of 1244 patients with MDR tuberculosis, 973 (78.2%) had known outcomes and 232 (18.6%) were lost to follow-up. Among those with known outcomes, treatment succeeded in 85.8% with plain MDR tuberculosis, 69.7% with initial resistance to either a fluoroquinolone or an SLI, 37.5% with acquired resistance to a fluoroquinolone or SLI, 29.3% with initial and 13.0% with acquired extensively drug-resistant tuberculosis (P < .001 for trend). In contrast, among those with known outcomes, treatment success increased stepwise from 41.6% to 92.3% as the number of drugs proven effective increased from ≤1 to ≥5 (P < .001 for trend), while acquired drug resistance decreased from 12% to 16% range, depending on the drug, down to 0%-2% (P < .001 for trend). In multivariable analysis, the adjusted odds of treatment success decreased 0.62-fold (95% confidence interval, .56-.69) for each increment in drug resistance and increased 2.1-fold (1.40-3.18) for each additional effective drug, controlling for differences between programs and patients. Specific treatment, patient, and program variables were also associated with treatment outcome. CONCLUSIONS: Increasing drug resistance was associated in a logical stepwise manner with poor treatment outcomes. Acquired resistance was worse than initial resistance to the same drugs. Increasing numbers of effective drugs, specific drugs, and specific program characteristics were associated with better outcomes and less acquired resistance.

Effects of dosage, comorbidities, and food on isoniazid pharmacokinetics in Peruvian tuberculosis patients.

Poor response to tuberculosis (TB) therapy might be attributable to subtherapeutic levels in drug-compliant patients. Pharmacokinetic (PK) parameters can be affected by several factors, such as comorbidities or the interaction of TB drugs with food. This study aimed to determine the PK of isoniazid (INH) in a Peruvian TB population under observed daily and twice-weekly (i.e., biweekly) therapy. Isoniazid levels were analyzed at 2 and 6 h after drug intake using liquid chromatography mass spectrometric methods. A total of 107 recruited patients had available PK data; of these 107 patients, 42.1% received biweekly isoniazid. The mean biweekly dose (12.8 mg/kg of body weight/day) was significantly lower than the nominal dose of 15 mg/kg/day (P < 0.001), and this effect was particularly marked in patients with concurrent diabetes and in males. The median maximum plasma concentration (Cmax) and area under the concentration-time curve from 0 to 6 h (AUC0-6) were 2.77 mg/liter and 9.71 mg · h/liter, respectively, for daily administration and 8.74 mg/liter and 37.8 mg · h/liter, respectively, for biweekly administration. There were no differences in the Cmax with respect to gender, diabetes mellitus (DM) status, or HIV status. Food was weakly associated with lower levels of isoniazid during the continuation phase. Overall, 34% of patients during the intensive phase and 33.3% during the continuation phase did not reach the Cmax reference value. However, low levels of INH were not associated with poorer clinical outcomes. In our population, INH exposure was affected by weight-adjusted dose and by food, but comorbidities did not indicate any effect on PK. We were unable to demonstrate a clear relationship between the Cmax and treatment outcome in this data set. Twice-weekly weight-adjusted dosing of INH appears to be quite robust with respect to important potentially influential patient factors under program conditions.

Congenital transmission of multidrug-resistant tuberculosis.

This article presents a case of multidrug-resistant tuberculosis (TB) in a Peruvian infant. His mother was diagnosed with disseminated TB, and treatment commenced 11 days postpartum. The infant was diagnosed with TB after 40 days and died at 2 months and 2 days of age. Congenital transmission of TB to the infant was suspected, because direct postpartum transmission was considered unlikely; also, thorough screening of contacts for TB was negative. Spoligotyping confirmed that both mother and baby were infected with identical strains of the Beijing family (SIT1).

Causas de hemoptisis en pacientes hospitalizados / Causes of hemoptysis in hospitalized patients

Objetivo. Determinar la variación a través del tiempo, de las causas de hemoptisis en pacientes hospitalizados. Material y Métodos. Estudio retrospectivo y transversal. Se revisó 251 historias clínicas de pacientes que fueron hospitalizados en el Hospital Dos de Mayo de Lima con diagnóstico de hemoptisis durante el período 2000-2011. Se recolectó variables como edad, sexo, procedencia, historia de tabaquismo, ocupación, antecedente de tuberculosis, entre otras. resultadOs. Las principales causas de hemoptisis fueron: tuberculosis activa (41,43 %), bronquiectasias (29,89%), cáncer pulmonar (7,97 %), micosis pulmonar (5,18 %), criptogénicas (4,38 %), bronquitis crónica (3,59 %), hidatidosis pulmonar (2,39 %) y neumonía (1,59 %). Se observó un incremento moderado en los casos de bronquiectasias y cáncer pulmonar en relación a los hallazgos reportados en el año 2000. Conclusión. Tuberculosis y bronquiectasias continúan liderando las principales causas de hemoptisis. Sin embargo, la proporción de tuberculosis como causa de hemoptisis ha disminuido en los últimos doce años y, a la vez, un incremento moderado de los casos de bronquiectasia y cáncer pulmonar.

Objective. To determine the over time variation of the causes of hemoptysis in hospitalized patients. Material and Methods. A retrospective and cross-sectional study was done. Two hundred and one medical histories of patients who were hospitalized in the Hospital Dos de Mayo of Lima with a diagnosis of hemoptysis during the period 2000-2011 was reviewed. Variables such as age, sex, origin, smoking habit, occupation, past history of tuberculosis, among others, were collected. results. The main causes of hemoptysis were: active TB (41,43 %), bronchiectasis (29,89 %), lung cancer (7,97 %), pulmonary mycosis (5,18 %), cryptogenic (4,38 %), chronic bronchitis (3,59 %), pulmonary hydatidosis (2,39 %) and pneumonia (1,59 %). It was observed a moderate increase in the cases of bronchiectasis and lung cancer in relation to the findings reported in the year 2000. Conclusin. Tuberculosis and bronchiectasis continue to lead the main causes of hemoptysis. However, the proportion of tuberculosis as a cause of hemoptysis has decreased in the last twelveyears and, at the same time, a moderate increase of cases of bronchiectasis and lung cancer is observed.

Second-line anti-tuberculosis drug concentrations for susceptibility testing in the MODS assay.

Multidrug-resistant tuberculosis (TB) threatens TB control worldwide. The microscopic observation drug susceptibility (MODS) assay is a low-cost, high-performance TB diagnostic tool for rapid liquid culture and direct isoniazid and rifampicin drug susceptibility testing (DST). The objective of this study was to explore the potential for extending the MODS assay to rapid second-line DST and to identify critical concentrations of candidate drugs for prospective testing. Sputum samples from 94 TB culture-positive patients receiving second-line TB agents were cultured following standardised MODS protocols, with a range of titrations of antimicrobial drugs added. Critical concentrations were determined using a modified Kaplan-Meier survival curve analysis. Candidate critical concentrations were determined for capreomycin (10 µg·mL(-1)), ciprofloxacin (1.25 µg·mL(-1)), cycloserine (40 µg·mL(-1)), ethambutol (10 µg·mL(-1)), ethionamide (5 µg·mL(-1)), kanamycin (5 µg·mL(-1)), para-aminosalicylic acid (10 µg·mL(-1)) and streptomycin (10 µg·mL(-1)). No cut-off point was identified for the other second-line drugs or for pyrazinamide. At particular concentrations of some second-line TB drugs this novel Kaplan-Meier analysis clearly differentiated populations that were susceptible or resistant. These candidate critical concentrations should now be tested in a range of epidemiological settings to define the performance of direct, second-line TB DST with MODS, offering potential low-cost second-line TB DST capacity.

Prevalence of and risk factors for resistance to second-line drugs in people with multidrug-resistant tuberculosis in eight countries: a prospective cohort study.

BACKGROUND: The prevalence of extensively drug-resistant (XDR) tuberculosis is increasing due to the expanded use of second-line drugs in people with multidrug-resistant (MDR) disease. We prospectively assessed resistance to second-line antituberculosis drugs in eight countries. METHODS: From Jan 1, 2005, to Dec 31, 2008, we enrolled consecutive adults with locally confirmed pulmonary MDR tuberculosis at the start of second-line treatment in Estonia, Latvia, Peru, Philippines, Russia, South Africa, South Korea, and Thailand. Drug-susceptibility testing for study purposes was done centrally at the Centers for Disease Control and Prevention for 11 first-line and second-line drugs. We compared the results with clinical and epidemiological data to identify risk factors for resistance to second-line drugs and XDR tuberculosis. FINDINGS: Among 1278 patients, 43·7% showed resistance to at least one second-line drug, 20·0% to at least one second-line injectable drug, and 12·9% to at least one fluoroquinolone. 6·7% of patients had XDR tuberculosis (range across study sites 0·8-15·2%). Previous treatment with second-line drugs was consistently the strongest risk factor for resistance to these drugs, which increased the risk of XDR tuberculosis by more than four times. Fluoroquinolone resistance and XDR tuberculosis were more frequent in women than in men. Unemployment, alcohol abuse, and smoking were associated with resistance to second-line injectable drugs across countries. Other risk factors differed between drugs and countries. INTERPRETATION: Previous treatment with second-line drugs is a strong, consistent risk factor for resistance to these drugs, including XDR tuberculosis. Representative drug-susceptibility results could guide in-country policies for laboratory capacity and diagnostic strategies. FUNDING: US Agency for International Development, Centers for Disease Control and Prevention, National Institutes of Health/National Institute of Allergy and Infectious Diseases, and Korean Ministry of Health and Welfare.

Community-based rapid oral human immunodeficiency virus testing for tuberculosis patients in Lima, Peru.

Among tuberculosis patients, timely diagnosis of human immunodeficiency virus (HIV) co-infection and early antiretroviral treatment are crucial, but are hampered by a myriad of individual and structural barriers. Community-based models to provide counseling and rapid HIV testing are few but offer promise. During November 2009-April 2010, community health workers offered and performed HIV counseling and testing by using the OraQuick Rapid HIV-1/2 Antibody Test to new tuberculosis cases in 22 Ministry of Health establishments and their household contacts (n = 130) in Lima, Peru. Refusal of HIV testing or study participation was low (4.7%). Intervention strengths included community-based approach with participant preference for testing site, use of a rapid, non-invasive test, and accompaniment to facilitate HIV care and family disclosure. We will expand the intervention under programmatic auspices for rapid community-based testing for new tuberculosis cases in high incidence establishments. Other potential target populations include contacts of HIV-positive persons and pregnant women.

Identifying multidrug resistant tuberculosis transmission hotspots using routinely collected data.

In most countries with large drug resistant tuberculosis epidemics, only those cases that are at highest risk of having MDRTB receive a drug sensitivity test (DST) at the time of diagnosis. Because of this prioritized testing, identification of MDRTB transmission hotspots in communities where TB cases do not receive DST is challenging, as any observed aggregation of MDRTB may reflect systematic differences in how testing is distributed in communities. We introduce a new disease mapping method, which estimates this missing information through probability-weighted locations, to identify geographic areas of increased risk of MDRTB transmission. We apply this method to routinely collected data from two districts in Lima, Peru over three consecutive years. This method identifies an area in the eastern part of Lima where previously untreated cases have increased risk of MDRTB. This may indicate an area of increased transmission of drug resistant disease, a finding that may otherwise have been missed by routine analysis of programmatic data. The risk of MDR among retreatment cases is also highest in these probable transmission hotspots, though a high level of MDR among retreatment cases is present throughout the study area. Identifying potential multidrug resistant tuberculosis (MDRTB) transmission hotspots may allow for targeted investigation and deployment of resources.

Pharmacokinetics of rifampin in Peruvian tuberculosis patients with and without comorbid diabetes or HIV.

For drug-compliant patients, poor responses to tuberculosis (TB) treatment might be attributable to subtherapeutic drug concentrations. An impaired absorption of rifampin was previously reported for patients with diabetes mellitus (DM) or HIV. The objectives of this study were to determine whether TB drug pharmacokinetics differed in Peruvian TB patients with DM or HIV. In this cross-sectional study, TB patients, recruited from health centers in Lima, Peru, had blood samples taken at 2 and 6 h after directly observed TB drug ingestion, to determine plasma concentrations of rifampin. Of 105 patients, 50 had TB without a comorbidity, 26 had coexistent DM, and 29 had coexistent HIV. Unexpectedly, the overall median 2- and 6-h levels of rifampin were 1.6 and 3.2 mg/liter, respectively, and the time to the peak concentration was 6 h (slow absorber) instead of 2 h (fast absorber) for 61 patients (62.2%). The geometric mean peak concentration of drug in serum (C(max)) was significantly higher in fast absorbers than in slow absorbers (5.0 versus 3.8 mg/liter; P = 0.05). The rifampin C(max) was significantly lower in male patients than in female patients (3.3 versus 6.3 mg/liter; P < 0.001). Neither slow nor fast absorbers with comorbidities (DM or HIV) had significantly different C(max) results compared to those of TB patients without comorbidities. An analysis of variance regression analysis showed that female gender (P < 0.001) and the time to maximum concentration of drug in serum (T(max)) at 2 h (P = 0.012) were independently correlated with increased exposure to rifampin. Most of this Peruvian study population exhibited rifampin pharmacokinetics different from those conventionally reported, with delayed absorption and low plasma concentrations, independent of the presence of an HIV or DM comorbidity.

[Cost analysis of rapid methods for diagnosis of multidrug resistant tuberculosis in different epidemiologic groups in Perú]. / Análisis de costos de los métodos rápidos para diagnóstico de tuberculosis multidrogorresistente en diferentes grupos epidemiológicos del Perú.

OBJECTIVES: To evaluate the costs of three methods for the diagnosis of drug susceptibility in tuberculosis, and to compare the cost per case of Multidrug-resistant tuberculosis (MDR TB) diagnosed with these (MODS, GRIESS and Genotype MTBDR plus®) in 4 epidemiologic groups in Peru. MATERIALS AND METHODS: In the basis of programmatic figures, we divided the population in 4 groups: new cases from Lima/Callao, new cases from other provinces, previously treated patients from Lima/Callao and previously treated from other provinces. We calculated the costs of each test with the standard methodology of the Ministry of Health, from the perspective of the health system. Finally, we calculated the cost per patient diagnosed with MDR TB for each epidemiologic group. RESULTS: The estimated costs per test for MODS, GRIESS, and Genotype MTBDR plus® were 14.83. 15.51 and 176.41 nuevos soles respectively (the local currency, 1 nuevos sol=0.36 US dollars for August, 2011). The cost per patient diagnosed with GRIESS and MODS was lower than 200 nuevos soles in 3 out of the 4 groups. The costs per diagnosed MDR TB were higher than 2,000 nuevos soles with Genotype MTBDR plus® in the two groups of new patients, and lower than 1,000 nuevos soles in the group of previously treated patients. CONCLUSIONS: In high-prevalence groups, like the previously treated patients, the costs per diagnosis of MDR TB with the 3 evaluated tests were low, nevertheless, the costs with the molecular test in the low- prevalence groups were high. The use of the molecular tests must be optimized in high prevalence areas.

Análisis de costos de los métodos rápidos para diagnóstico de Tuberculosis multidrogorresistente en diferentes grupos epidemiológicos del Perú / Cost analysis of rapid methods for diagnosis of multidrug resistant Tuberculosis in different epidemiologic groups in Perú

Objetivos. Evaluar los costos de tres métodos diagnósticos para susceptibilidad a drogas antituberculosas y comparar el costo por caso de tuberculosis multidrogorresistente (TB MDR) diagnosticado con estos (MODS; GRIESS y Genotype MTBDR plus ® en cuatro grupos epidemiológicos en el Perú. Materiales y métodos. En base a cifras programáticas, se dividió a la población en cuatro grupos: pacientes nuevos de Lima/Callao; nuevos de otras provincias; los antes tratados de Lima/Callao y de otras provincias. Se calcularon los costos de cada prueba en base a la metodología estándar utilizada por el Ministerio de Salud, desde la perspectiva de los servicios de salud. Basado en ello, se calculó el costo por paciente TB MDR diagnosticado para cada grupo epidemiológico. Resultados. Los costos estimados por prueba para MODS, GRIESS, y Genotype MTBDR plus ® fueron de 14,83; 15,51 y 176,41 nuevos soles, respectivamente. El costo por paciente TB MDR diagnosticado con GRIESS y MODS fue menor a los 200 nuevos soles en tres de los cuatro grupos. El costo por TB MDR diagnosticado fue de más de 2000 nuevos soles con el Genotype MTBDR plus ® en los dos grupos de pacientes nuevos y, menores a 1000 nuevos soles en los grupos de pacientes antes tratados. Conclusiones. En grupos de alta prevalencia, como son los pacientes antes tratados, los costos por caso diagnosticado de TB MDR con las tres pruebas evaluadas fueron bajos, sin embargo, con la prueba molecular en los grupos de baja prevalencia, fueron elevados. El uso de las pruebas moleculares debe optimizarse en grupos de altas prevalencias.

Objectives.To evaluate the costs of three methods for the diagnosis of drug susceptibility in tuberculosis, and to compare the cost per case of Multidrug-resistant tuberculosis (MDR TB) diagnosed with these (MODS, GRIESS and Genotype MTBDR plus ® in 4 epidemiologic groups in Peru. Materials and methods.In the basis of programmatic figures, we divided the population in 4 groups: new cases from Lima/Callao, new cases from other provinces, previously treated patients from Lima/Callao and previously treated from other provinces. We calculated the costs of each test with the standard methodology of the Ministry of Health, from the perspective of the health system. Finally, we calculated the cost per patient diagnosed with MDR TB for each epidemiologic group. Results. The estimated costs per test for MODS, GRIESS, and Genotype MTBDR plus® were 14.83. 15.51 and 176.41 nuevos soles respectively (the local currency, 1 nuevos sol=0.36 US dollars for August, 2011). The cost per patient diagnosed with GRIESS and MODS was lower than 200 nuevos soles in 3 out of the 4 groups. The costs per diagnosed MDR TB were higher than 2,000 nuevos soles with Genotype MTBDR plus ® in the two groups of new patients, and lower than 1,000 nuevos soles in the group of previously treated patients. Conclusions. In high-prevalence groups, like the previously treated patients, the costs per diagnosis of MDR TB with the 3 evaluated tests were low, nevertheless, the costs with the molecular test in the low- prevalence groups were high. The use of the molecular tests must be optimized in high prevalence areas.

Vigilancia nacional de la resistencia a medicamentos antituberculosos, Perú 2005-2006 / National surveillance of anti-tuberculosis drug resistance, Peru 2005-2006

Objetivo. Determinar la prevalencia de resistencia a medicamentos antituberculosos en el Perú. Materiales ymétodos. Se realizó un muestreo por conglomerados en las 33 regiones de salud de Perú. Se utilizó el método de lasproporciones de Canetti en medio sólido Lowenstein Jensen para la susceptibilidad de Mycobacterium tuberculosis a medicamentos antituberculosos con isoniacida (INH) rifampicina (RMP), estreptomicina (SM) y etambutol (EMB). Las cepas con resultado de TB MDR se sometieron a susceptibilidad a medicamentos de segunda línea por el método delas proporciones en agar 7H10, en placas. Resultados. Se analizaron 1809 cultivos de pacientes nuevos y 360 de antes tratados. El 51,6 por ciento residía en Lima y el 59,3 por ciento fueron varones. La prevalencia nacional de la resistencia primaria fue de 23,2 por ciento (IC95 por ciento: 21,3 - 25,1) y la resistencia adquirida fue de 41,7 por ciento (IC95 por ciento: 36,5 - 46,8). Se detectó 180 casos de TB MDR de los cuales la prevalencia de TB MDR primaria fue 5,3 por ciento (IC95 por ciento: 4,2 - 6,3) y la adquirida fue de 23,6 por ciento (IC95 por ciento:19,2 û 28,0). El 20 por ciento de aislamientos de pacientes nunca tratados en Lima fueron resistentes a INH o RIF. La resistencia global y la TB MDR primarias fueron más prevalentes en Lima que en el resto del país. La TB XDR estuvo presente en el 5,9 por ciento de pacientes con TB MDR y el 36 por ciento de las cepas de TB MDR fueron resistentes a por lo menos una droga de segunda línea. Conclusiones. Comparado con los estudios previos, la resistencia a drogas antituberculosas primaria y adquirida se ha incrementado significativamente en los últimos 10 años en Perú.

Objective. To determine the anti-tuberculosis drug resistance prevalence in Peru. Material and methods. We performed a conglomerated sampling in 33 health regions from Peru. We used a Canneti proportions method in solid medium L-J for testing Mycobacterium tuberculosis susceptibility with isoniazid (INH) rifampicin (RMP), streptomycin (SM) and ethambutol (EMB). Strains with TB MDR was evaluated to second line drug susceptibility by proportion methods in 7H10 agar in plates. Results. We analyzed 1809 cultures from new patients and 360 pre treated. 51.6 coming from Lima and 59.3 per cent were males. The national prevalence of primary resistance was 23.2 per cent (CI95 per cent: 21.3 - 25.1) and acquired resistance was 41.7 per cent (95 per cent CI: 36.5 - 46.8). We detected 180 TB MDR cases, the prevalence of primary TB MDR was5.3 per cent (95 per cent CI: 4.2 - 6.3) and acquired was 23.6 per cent (95 per cent CI: 19.2 - 28.0). 20% of never treated patients isolated wereresistant to INH or RIF. Global resistance and primary TB MDR were more prevalent in Lima than rest of the country. TB XDR was present in 5.9 per cent of patients with TB MDR and 36 per cent of TB MDR strains were resistant at least one secondline drug. Conclusions. Compared with previous studies, primary and acquired anti-tuberculosis drug resistant have significantly increased in the last 10 years in Peru.

Improved diagnosis of pleural tuberculosis using the microscopic- observation drug-susceptibility technique.

Tests for pleural tuberculosis are insensitive and expensive. We compared nonproprietary microscopic-observation drug-susceptibility (MODS) culture with Löwenstein-Jensen culture for evaluation of pleural specimens. MODS culture was associated with greatly increased diagnostic sensitivity and shorter time to diagnosis, compared with Löwenstein-Jensen culture (sensitivity of culture of biopsy specimens, 81% vs.51%; time to diagnosis, 11 days vs. 24 days; P < .001). The MODS technique is inexpensive, allows drug-susceptibility testing, and is a considerably improved diagnostic method for pleural tuberculosis.

Evaluación de la prueba de ELISA para anticuerpos contra el antígeno micobacterial P-90 en el antígeno de tuberculosis / Evaluation of ELISA antibodies test against P-90 mycobacterial antigen in tuberculosis diagnosis

OBJETIVO: Determinar la sensibilidad y especificidad del diagnóstico serológico mediante la detección de IgA específica para tuberculosis (TB). DISEÑO: Estudio observacional, prospectivo, de casos y controles. LUGAR: Hospital Nacional Dos de Mayo, en el período de octubre de 1998 hasta marzo de 1999. MATERIALES Y MÉTODOS: Se evaluó 81 casos de tuberculosis demostrados mediante frotis y cultivo y/o biopsia positiva para bacilo de Koch (BK) y 86 controles demostrados sanos. Se utilizó la prueba de diagnóstico serológico de TB mediante la respuesta de IgA al antígeno P-90, con la prueba de enzima inmunoabsorbente (kit Kreatech EIA-TB, Amsterdam, Holanda), preparada a partir del BCG. RESULTADOS: La sensibilidad de la prueba es 96,3 por ciento, la especificidad 77,9 por ciento. CONCLUSIONES: La detección de inmunoglobulina A mediante el antígeno clase Kp-90 Im CRAC del Mycobacterium tuberculosis no es de utilidad complementaria en el diagnóstico de tuberculosis, especialmente en el gran porcentaje de pacientes que es tratado como BK negativo.