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.

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.
References in periodicals archive ?
In total, this study used 3,500 observations, both in First window period and Second window period, for calculating Hurst Exponent values.
Occult hepatitis B virus infection/carriage (OBI) is characterized by the presence of very low levels of HBV DNA in plasma and/or in liver, with undetectable HBsAg using the most sensitive commercial assays, with or without antibodies to antiHBc or hepatitis B surface antigen (anti-HBs) outside the pre-seroconversion window period.
That accounts for approximately 50 per cent reduction in window period for HIV, 72 per cent for Hepatitis C and 34 per cent for Hepatitis B.
The reduction in the window period of up to five days by fourth-generation HIV assays has been achieved by the development of an HIV "combo" assay that detects both HIV antibodies and the HIV p24 antigen.
The New Loft Law window period is January 1, 2008 through December 31, 2009.
Days before the ban started, the city government modified the ban and introduced a window period from 10 a.
It is during this four-hour window period that the sun's rays are at their most intense.
With respect to a foreign corporation, the 90-day window period begins on the first day of the foreign corporation's tax year as long as all of the controlling domestic shareholders under exam have been under exam for at least 12 consecutive months as of the first day of that tax year.
This is not limited to the transfer window period but obviously outside the transfer window it would have to be a player out of contract that comes in.
We have only one option for the reduction of disability from acute stroke in the form of tissue plasminogen activator which has a very narrow window period of 3 to 4.
Qatar Primary Materials Company's (QPMC) Gabbro Terminal Operations have surpassed the handling of aggregate cargo in excess of 100,000 tonnes twice in a row within a 24-hour window period last month, the company said in a release last night.