window period

(redirected from Window Periods)
Also found in: Financial.

window period

1. a critical interval of time.
See also: window (2).
See also: incubation period.
2. the interval that elapses between infection or inoculation with a pathogen and the onset of symptoms or of detectability of infection by laboratory testing.
See also: incubation period.
3. the time between infection with a bloodborne virus and the appearance of specific laboratory evidence of infection in a specimen of blood obtained from the asymptomatic host for the purpose of diagnostic screening, or in blood or blood products donated by the host.

In clinical medicine and blood banking, the window period (sense 3 above) refers to the earlier part of the incubation period of an infectious disease, during which the host is or may be infectious to others, but where the presence of infection has not yet caused symptoms and cannot be detected by laboratory testing. Bloodborne viral infections, particularly those due to human immunodeficiency virus (HIV-1) and hepatitis C virus (HCV), can be transmitted sexually, by sharing of needles among intravenous drug abusers, from mother to fetus, by transfusion of blood or blood products, and by accidental needlestick injuries among health care workers. The window periods of these infections are of critical importance in the early detection of transmissible infection in asymptomatic people and in the screening of donor blood. Because those harboring these viruses typically become infectious well before the end of the window period, the challenge is to shorten the period as much as possible by the use of maximally sensitive tests. An important limitation in determining the window period is the difficulty of fixing its beginning, which requires precise knowledge of the time when infection was acquired-often not available except in cases of accidental exposure to body fluids in health care workers, as in needlestick injuries. The definition of the window period has evolved with the emergence of increasingly sensitive tests to detect infection. Early definitions were based on the interval between infection and the appearance of detectable antibody to virus. The development of tests for the presence of viral antigen in plasma shortened the window period, permitting detection of viral material and infectivity before the occurrence of an immune response. Nucleic acid testing, involving detection of viral DNA or RNA after amplification of the specimen by polymerase chain reaction, has reduced the window period for detection of HCV from 82-25 days and of HIV from 22-12 days.

Infectious disease The period during which a pathogen can be detected in a patient specimen by nucleic acid testing, but not by serology, as the patient’s immune system has not yet responded to the pathogen by producing measurable levels of antibodies
Toxicology The period which corresponds to the interval between ingestion of lethal quantities of a drug or toxin, and development of irreversible organ damage

window period

AIDS An interval between initial infection of HIV and development of anti-HIV-1 antibodies, usually 3–6 months Immunology An interval between the time of inoculation or exposure to a microorganism, usually viral, and the ability to detect its presence by serologic assays which detect the production of antibodies by the host, or the presence of the pathogen's antigens

win·dow pe·ri·od

(windō pērē-ŏd)
1. Critical time interval.
2. Time between infection with a bloodborne virus and the appearance of specific laboratory evidence of infection in a specimen of blood obtained from the asymptomatic host for the purpose of diagnostic screening, or in blood or blood products donated by the host.

window period,

n the period between when a party is exposed to an infectious organism and when that organism becomes detectable via a serum marker. See incubation period.
References in periodicals archive ?
This rule drastically limits the ability of a foreign corporation to change its accounting method in one of the window periods under the automatic or nonautomatic procedures.
For significant industry issues, taxpayers should expect that this type of practice will occur more frequently in order to prevent them from changing under the window periods.
At a minimum, the IRS should clarify the effect of a Supreme Court decision occurring during the various window periods under the revenue procedure.
Furthermore, the rules provide various window periods within which voluntary method changes may be secured, following contact for examination but before a compulsory change imposed by the Commissioner.
In all other circumstances, a taxpayer could request a change only during the 30-day, 90-day or 120-day window periods.
84-74, taxpayers under examination were precluded from filing a Category A method change unless they were in either the 30-day or 120-day window periods.
The Company currently expects to purchase the remaining shares under the $1 billion program through open market purchases, subject to trading window periods and the program's June 30, 2007 expiration date.
The plans cover only options that are due to expire on September 16, 2006, and allow the officers to sell Sensient stock acquired as a result of exercising the options during two window periods starting in April 2006 and ending in August 2006.
Taxpayers that did not previously file Forms 3115 and are currently under examination or subsequently come under examination must file a Form 3115 with the examining agent within the first 90 days of the examination or within any of the window periods available under Rev.
The plans cover only options that are due to expire on September 18, 2005, and allow the officers to sell Sensient stock acquired as a result of exercising the options during two window periods starting in April 2005 and ending in August 2005.
The special window periods do not apply if any of the taxpayer's returns are under consideration by an IRS appeals office, or are the subject of litigation before a Federal court, unless written permission is obtained from the appeals officer or IRS attorney handling the case.