Abstract: A test kit is disclosed for analyzing a patient's saliva to determine the patient's risk of tooth decay, which contains: (a) a support; (b) an absorbent material in contact with said support and capable of removing saliva from the mouth and of absorbing the saliva; (c) a composition coated on said absorbent material, said composition soluble in saliva and capable of reaction inside the mouth of the patient with the saliva to reduce the pH of the saliva; and (d) a color scale for determining outside of the mouth of the patient the pH of the saliva absorbed by the absorbent material in which the composition is dissolved to measure the reaction of the composition with the saliva in the patient's mouth to determine the patient's risk of tooth decay.