This book discussed the principles of Nucleic Acid technique (NAT) generally and Transcription Mediated Amplification (TMA) specifically as a methods for screening blood donors. It covers the very updated techniques and completely revised to reflect the latest research in field. Its extent of information, concise, and consideration to relevant technical detail allow the book to be an excellent starting point and an ongoing resource for Researchers and postgraduate students. We hope you will use this book frequently in your research or practice. Any comments or input will always be welcomed and respected.