IT HAS taken 100 years, but at last we have developed a quick and reliable test for tuberculosis.
Researchers have struggled to find an alternative to the standard tuberculin skin test, developed a century ago by the German bacteriologist Robert Koch. It involves injecting a witch’s brew of 200 or so proteins extracted from Mycobacterium tuberculosis, the bacterium that causes TB, into the skin of the arm. Infected people develop a red lump after about a week.
However, deciding whether a mild reaction is severe enough to count as a positive result is subjective. What’s more, people who have…
