By the turn of the 20th century, clinical laboratories were in existence, and the use and number of analytes found in blood for clinical diagnosis and treatment was expanding. In 1908 Todd and Sanford published the first edition of their book Diagnosis by Laboratory Methods. In addition to procedures for laboratory testing, the manual described general techniques for obtaining blood by venipuncture and skin stick. By the 1920s, the use of venipuncture for diagnostic testing had become widespread, and the term phlebotomy took on a whole new meaning.
