Rules of thumb for testing when sensitivity and specificity are 80–90%, and positive and negative likelihood ratios 4–9 and 0.3–0.1.

Accuracy: The accuracy of a test is its ability to differentiate the patient and healthy cases correctly. To estimate the accuracy of a test, we should calculate the proportion of true positive and true negative in all evaluated cases.

Accuracy = (sensitivity) (prevalence) + (specificity) (1 – prevalence). The numerical value of accuracy represents the proportion of true positive results (both true positive and true negative) in the selected population. An accuracy of 99% of times the test result is accurate, regardless positive or negative.

Medical laboratory testing plays a crucial role in the early detection, diagnosis and treatment of disease in patients. If a patient routinely submits to lab testing, this may allow doctors to respond swiftly with preventative treatment, which could save the patient time, money, and possibly sickness in the future.

Early and accurate diagnosis of infectious disease is critically important because: Diagnosis can improve the effectiveness of treatments and avoid long-term complications for the infected patient. Undiagnosed patients can unknowingly transmit the disease to others.

Steps to diagnosis

1. taking an appropriate history of symptoms and collecting relevant data.
2. physical examination.
3. generating a provisional and differential diagnosis.
4. testing (ordering, reviewing, and acting on test results)
5. reaching a final diagnosis.
6. consultation (referral to seek clarification if indicated)

cancer: 14% diabetes: 2% drug & alcohol abuse: 2% heart disease: 1%

The most common type of viral disease is the common cold, which is caused by a viral infection of the upper respiratory tract (nose and throat). Other common viral diseases include: Chickenpox. Flu (influenza)

Infectious diseases are caused by microscopic germs (such as bacteria or viruses) that get into the body and cause problems. Some — but not all — infectious diseases spread directly from one person to another. Infectious diseases that spread from person to person are said to be contagious.

Infections That Aren’t Contagious

• 1 / 13. Contagious or Not? Some germs are contagious.
• 2 / 13. Legionnaires Disease.
• 3 / 13. Ear Infections.
• 4 / 13. Urinary Tract Infection.
• 5 / 13. Vaginal Yeast Infection.
• 6 / 13. Sinus Infection (Sinusitis)
• 7 / 13. Salmonella.
• 8 / 13. E.

Bacterial Infections Symptoms persist longer than the expected 10-14 days a virus tends to last. Fever is higher than one might typically expect from a virus. Fever gets worse a few days into the illness rather than improving.