MONTREAL/WASHINGTON (Reuters) - A global aviation manual now under review by a UN body suggests global guidelines calling for the use of highly reliable tests when screening passengers to detect the novel coronavirus ahead of flights, three sources familiar with the matter said.Carriers and airports are pushing for uniform global testing guidelines to waive strict quarantine requirements that are decimating travel, with airline trade group IATA forecasting a 66% decline in 2020 air traffic because of the pandemic. Travel restrictions and the use of testing now vary globally. Certain airlines require passengers to obtain a negative test, even as some countries allow visitors in without quarantine, while others bar all non-essential foreigners. The International Civil Aviation Organization (ICAO) Manual on Testing and Cross Border Risk Management Measures, expected in November, would offer voluntary technical guidance but not oblige countries to remove quarantines. The manual is not expected to suggest specific tests, such as antigen or polymerase chain reaction (PCR), the sources said. Instead, it would recommend passengers be screened using a test with a sensitivity and specificity of 95% so there would be few false positives and negatives, the sources added.