W. Va. Code § 17C-25-4
When a law-enforcement officer has reason to believe a person has committed an offense prohibited by §17C-25-2 of this code, the law-enforcement officer may require the person to submit to a preliminary breath analysis for the purpose of determining that person's blood alcohol content. The law-enforcement officer shall administer the breath analysis as soon as possible after he or she has a reasonable belief that the person has been operating an aircraft while under the influence of alcohol, controlled substances, or drugs. Any preliminary breath analysis required under this section shall be administered with a device and in a manner approved by the Bureau of Public Health for that purpose. The results of a preliminary breath analysis shall be used solely for the purpose of guiding the law-enforcement officer in deciding whether an arrest should be made. When a person is arrested following a preliminary breath analysis, the tests shall be administered in accordance with the provisions of this article.
W. Va. Code § 17C-25-4