1. CLSI. Blood Collection on Filter Paper for Newborn Screening Programs; Approved Standard—Sixth Edition. CLSI Document NBS01-A6. Clinical and Laboratory Standards Institute: Wayne, PA, 2013.
2. US National Library of Medicine. Genetics home reference—your guide to understanding genetic conditions: newborn screening. http://ghr.nlm.nih.gov/nbs. Accessed 14 January 2015.
3. Texas Department of State Health Services. Responsibilities of the physician (or other person attending a newborn, if no physician is present) and collection of first and second specimen. Texas Administrative Code, Rule §37.56. http://texreg.sos.state.tx.us/public/readtac$ext.TacPage?sl=R&app=9&p_dir=&p_rloc=&p_tloc=&p_ploc=&pg=1&p_tac=&ti=25&pt=1&ch=37&rl=56. Accessed 14 January 2015.
4. Oregon Secretary of State. Clinical laboratories—time of collecting specimens for testing infants. Oregon Administrative Rules, 333-024-0225. http://arcweb.sos.state.or.us/pages/rules/oars_300/oar_333/333_024.html. Accessed 14 January 2015.
5. Illinois Department of Public Health. Newborn screening practitioners manual. http://www.idph.state.il.us/HealthWellness/Newborn_Screening_Practitioners_Manual.pdf. Accessed 14 January 2015.