Quest Diagnostics Incorporated , the nation's leading provider of diagnostic testing, information and services, today announced a new, proprietary diagnostic testing technique to help physicians diagnose genetic metabolic disorders, such as phenylketonuria (PKU) and homocystinuria. Genetic metabolic disorders can impair a child's mental and physical development. The new technique measures amino acids in blood plasma, urine or cerebral spinal fluid by employing a combination of liquid chromatography and mass spectrometry.

Physicians may also use amino acid quantitation tests on individuals whose ability to process nutrients may be impaired, such as those undergoing chemotherapy treatments for cancer, the elderly, and individuals with gastrointestinal illnesses.

The new technique is an advance over conventional test methods, providing greater diagnostic sensitivity and specificity for detecting a range of metabolic and nutritional disorders. The technique can be used to measure and report up to 47 individual amino acids, depending on the condition to be tested and type of specimen. The new testing method also overcomes the problem of interference from medications and diet, which, when using conventional testing methods, often hinders accurate analysis. In addition, the new methodology can detect amino acid levels as low as one micromole per liter, which enhances its usefulness for detecting nutritional deficiencies compared to conventional methods.

"We believe this new testing technique will improve nutritional monitoring and enhance the detection of several inherited metabolic disorders that can impair a child's mental and physical development," said Joyce Schwartz, M.D., vice president and chief laboratory officer. "We also expect improved turnaround times to enhance diagnosis and treatment."

Researchers at Quest Diagnostics Nichols Institute, the company's esoteric diagnostic testing, research and development center, developed the new methodology. The company recently began to market the technique to hospital physicians with an emphasis on pediatric, neonatology, genetic, oncology and gastroenterology practices.

Quest Diagnostics has established normal ranges by age and sample type, enabling clinicians to evaluate individuals at all ages for a range of nutritional deficiencies and for a number of inborn errors of metabolism.

About Quest Diagnostics

Quest Diagnostics is the leading provider of diagnostic testing, information and services that patients and doctors need to make better healthcare decisions. The company offers the broadest access to diagnostic testing services through its national network of laboratories and patient service centers, and provides interpretive consultation through its extensive medical and scientific staff. Quest Diagnostics is a pioneer in developing innovative new diagnostic tests and advanced healthcare information technology solutions that help improve patient care. Additional company information is available at www.questdiagnostics.com.

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