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HUMAN PAPILOMA VIRUS (HPV)

Categoría: Infectious diseases.
Días hábiles de entrega: 10
 

Genital swab, buccal swab, genital brush, fresh biopsy, paraffin biopsy and urine (male patients only).

Store and ship samples at temperatures between approximately 4-8 ° C; refrigerant gels or refrigerator ice can be used for it. Fresh biopsies: Store at -20º C immediately or at 4º C in laboratory lysis buffer supplied.

DNA extraction from the sample using commercial kits.

PCR-RFLP using primers selected in the open reading fragment L1 ORF, described by Volker, et al. 1996 and Coutlee et al 2002, and its visualization in agarose gel with ethidium bromide staining.

10 working days.

A positive HPVhigh-risk test indicates that the patient may be infected with HPV genotypes (16, 18, 30, 31, 33, 35, 39, 45, 51, 52, 53, 56, 58, 59, 60, 68, 73, 82) which are associated with cervical cancer and precursor lesions thereof. Mixed infections with other genotypes may occur; the results should always be correlated with cytology.

A positive low-risk HPV (6, 11, 40, 42,43, 44, 57, 61, 70, 72, 81) indicates lesions associated with condylomata. The HPV typing is conceived for its use as a complementary test and in no case as a single diagnostic criterion; therefore, in conjunction with cytological and histological studies, it is very effective in predicting the progression of cervical lesions, differentiating those that mean a high risk of those involving a low risk in relation to cancer. Carefully analyze a negative result, may be caused by a poorly drawn sample or with DNA below the detection limit of the test. The HPV screening test is aimed at women and men primarily once they initiate their active sex life, and should be repeated periodically, especially if they frequently change partners. The high sensitivity and specificity of the PCR makes possible the detection and typing of the virus at a very early stage of infection even though there are still no cytological abnormalities; in infected patients, it is important to perform colposcopy-directed cytological tests where possible. The HPV screening test should be integrated into the classic arsenal of Pathological Anatomy labs to facilitate the management of cases with lesions that are difficult to classify histologically.

Genomik Laboratory has validated the test with positive and negative commercial controls; however, a negative result does not exclude the presence of HPV DNA below the sensitivity limit of the test, or the possible presence of inhibitors of the PCR reaction. The reliability of the test is guaranteed by the use of sophisticated systems for the prevention of contamination, in addition to the incorporation of an internal control of each test to avoid the appearance of false negatives.

Human papillomavirus (HPV) infection is frequently transmitted through sexual contact and its prevalence is extremely high, millions of thousands of HPV infections occur each year. HPV is directly involved in the development of condylomas and squamous intraepithelial lesions (LIE) being identified as a risk factor present in more than 90% of cases diagnosed with cervical cancer. HPV is a virus with a circular genome that has a double-stranded deoxyribonucleic acid (DNA), which selectively infects epithelial cells. The clinical form is usually manifested as flat or verrucous, whitish lesions in especially humid genital areas visible to the eye, but the subclinical form may also occur where the lesion may be flat or of different topographic (atypical) forms, which are only visible in colposcopy. In those cases where the tissue damage is absent, a phase called latent or hidden infection, can only be diagnosed by isolation of the DNA from the cells where HPV has been replicated. The degree of injury is related to specific HPV genotypes. There are more than 150 genotypes and approximately 40 can affect the genital tract.

Coutlee F, Gravitt P, Kornegay J, Hankins C, Richardson H, Lapointe N, Voyer H, Franco E. Use of PGMY primers in L1 consensus PCR improves detection of human papillomavirus DNA in genital samples.J Clin Microbiol. 2002 Mar;40(3):902-7.

Volker Adams, Moll Carlo, Mirka Schmid, Celestino Rodrigues, Rita Moos, ADN Jakob Briner. Detection ADN Typing of Human Papillomavirus in Biopsy ADN Cytological Specimens by Polymerase Chain Reaction ADN Restriction Enzyme Analysis: a method suitable for semiautomation. J Med Virol. 1996 Feb; 48(2):161-70.



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