Specimen Validity: What Does CR Mean on a Drug Test?
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4 min read
Millions of drug tests are conducted annually for employment and legal reasons [1.3.3]. When reviewing results, many ask, **what does CR mean on a drug test?** This abbreviation refers to creatinine, a crucial marker for ensuring the test sample itself is valid and has not been tampered with [1.2.1, 1.2.5].
