2. Relación entre el resultado de una prueba diagnóstica y la
presencia o ausencia de una enfermedad.
Resultado de la prueba
Verdadero diagnóstico
Enfermo Sano
Positivo
Verdaderos Positivos
(VP)
Falsos Positivos
(FP)
Negativo
Falsos Negativos
(FN)
Verdaderos Negativos
(VN)
4. Resultados de la exploración y biopsia gástrica de una
muestra de pacientes con sospecha de cáncer de
estomago.
Resultado de
endoscopia
Resultado de la biopsia gástrica
Cáncer Patología benigna Total
Anormal 800 400 1200
Normal 500 1400 1900
Total 1300 1800 3100
5. Resultados de la aplicación del test de HTLV I en una
población de alta prevalencia.
Resultado del test
Verdadero diagnóstico
HTLV+ HTLV - Total
Positivo 50000 10000 60000
Negativo 6000 190000 196000
Total 56000 200000 256000
6. SECCIÓN DE REFERENCIA
SECCIÓN DE REFERENCIA
Pregunta 1
• 1.- A test for coronary artery disease is positive in 180 of 200 people with known
coronary artery disease and negative in 140 of 200 people who do not have
disease. If the test result returns positive, what is the likelihood that coronary
artery disease is present?
A. 50%
B. 70%
C. 75%
D. 90%
7. SECCIÓN DE REFERENCIA
SECCIÓN DE REFERENCIA
Pregunta 2
• A 65 year –old man with a history of coronary artery disease complains of severe substernal chest
pain for the past 24 hours. He states that the pain also radiates down the left arm. A blood sample
is drawn for electrolytes and serum creatine kinasen(CK) isenzyme MB. Owing to technical
difficulties in collecting the blood, the sample is visibly hemolized. The serum potassium and CK
isoenzyme MB are both increased. An electrocardiogram (ECG) shows a Q wave in the anterior
leads; however, there are no T wave abnormalities present. Which of the following correctly
describes the test result?
Serum potasium Serum CK-MB
A False negative True positive
B False positive False positive
C False positive True positive
D True positive False positive
E True positive True positive
8. SECCIÓN DE REFERENCIA
SECCIÓN DE REFERENCIA
Pregunta 3
• Study the data in Table on a test performed on 100 patients who are known to have
disease X and a control group containing 100 people who do not have disease X. Which
of the following conclusions can be drawn from this study?
Disease X Control group
Positive test 100 20
Negative test 0 80
A. A negative test result excludes disease X.
B. A positive test result confirms disease X
C. It is poor screening test for disease X
D. The predictive value of a positive test result is
100%
E. The prevalence of disease is 60%
