window period

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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.

Farlex Partner Medical Dictionary © Farlex 2012
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
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.

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
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.

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.
Medical Dictionary for the Dental Professions © Farlex 2012
References in periodicals archive ?
Where taxpayers did not make affirmative hedging identifications, taxpayers should be permitted a window period within which to undertake remedial action to make hedging identifications under the general rule of the proposed hedging regulations, subject to limitations based on reasonableness and consistency.
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.
92-20 provides a new window period, pursuant to which taxpayers under examination may file accounting method changes other than Designated A's during the first 90 days of the examination.
Estrada, however, allowed a two-week trial for a window period, from 10 a.m.
to 5 p.m., a two-hour extension from the previous window period of 10 a.m.
If, however, the item is recognized during the window period, the loss, at least in part, is preserved for future carryforward.
But Sening Dimate, president of Confederation of Truckers Association, and Teddy Gervacio of Integrated North Harbor Truckers Association said the revised truck ban would still affect their operations because the window period was not still enough.
Further, any election to receive a cash payment must be made during a 10-day window period, i.e., the third through twelfth day following the date of the company's quarterly earnings release.
MANILA -- Following a meeting with exporters and other government officials on Thursday, the City of Manila decided to temporarily modify its daytime truck ban by allowing truckers to ply their routes between a window period of 10 a.m to 3 p.m.
The purchases were made during an open window period and in full compliance with all company and legal guidelines.
Among other provisions, the law prescribes a specific window period of three to 20 days for processing permits, depending on how complex or technical the papers are.
We are improving one match at a time," he said.Selebwa said the more than 10 new players, mostly young whom the club had signed during the window period were being incorporated in the team one after the other to give the experienced ones more opportunity.