Positive Schick test indicates:

Schick Test: The immune status of a person can be assessed by Schick's test. The test is performed by intradermal injection of 0.1 mL of purified standardized toxin. If the patient has no anti toxin, the toxin will cause inflammation at the site 4 to 7 days later. If no inflammation occurs, antitoxin is present and the patient is immune. A positive schick test indicates susceptible to diphtheria. Ref: Levinson W. (2012). Chapter 17. Gram-Positive Rods. In W. Levinson (Ed),Review of Medical Microbiology & Immunology, 12e.