Type of test  Fluid analysis

Normal findings  No HPV present

 Test explanation and related physiology

 An HPV test is performed to identify genital HPV infection in a woman with an abnormal PAP smear . HPV DNA incorporates itself into the cervical cell genome, promoting its effects through activation of oncogenes and suppression of host cell immune response.

Genital HPV strains are divided into two groups (low, or nononcogenic risk, and high, or oncogenic risk), based on their oncogenic potential and ability to induce viral-associated tumors. Low-risk strains (HPV 6, 11, 42, 43, and 44) are associated with condylomata (genital warts) and low-grade cervical changes, such as mild dysplasia. Lesions caused by low-risk HPV infection have a high likelihood of regression and little potential for progression and are considered of no or low oncogenic risk. High risk strains (HPV 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, and 68) are associated with intraepithelial neoplasia and are more likely to progress to severe lesions and cervical cancer.

A clear causal relationship has been established between HPV infection and cervical cancer. Of the high-risk HPV strains, HPV 16 and 18 are the most carcinogenic and most prevalent. High grade cervical intraepithelial lesions are most commonly associated with HPV 16 and 18, yet these strains are also frequently found to be the etiologic factor in minor lesions and mild dysplasia. Women who have normal Pap tests results and no HPV infection are at a very low risk (0.2%) for developing cervical cancer.

Numerous sources indicate that more than 60% of women with an abnormal Pap smear result will test positive for high risk HPV. If the HPV test result is positive, the woman should undergo colposcopy to look for a more serious cervical lesion, such as cancer. It is well known that HPV infection in younger women is more prevalent and often spontaneously regresses, particularly in those younger than the age of 30 years. In contrast, persistent high-risk infection peaks in women older than 30 years. As a result, recent screening guidelines recommend that HPV testing be reserved for clinical use in the evaluation of women older than the age of 30 years and perhaps for younger women with high-grade squamous intraepithelial lesions. A combination of cervical cytology and HPV DNA screening is also appropriate screening for women aged 30 years and older.

Whether HPV testing can replace conventional Pap cytologic testing for cervical cancer screening awaits further study. Though current high-risk HPV DNA testing methods generally provide very good sensitivity, specificity is limited. DNA testing detects both transient and persistent (transforming) infections. Transient infections will be cleared by competent immune systems of the patient. DNA testing, therefore, can lead to positive results in patients who harbor unimportant transient HPV infections that lead to unnecessary invasive procedures such as colposcopy and biopsy in some women. Persistent or chronic HPV infections are those that lead to cellular disruption, proliferation, mutations, and eventual transformation into a neoplasm. The oncoproteins responsible for this transformation are the early proteins 6 and 7 (E6 and E7). HPV mRNA testing detects E6 and E7. When high risk HPV DNA testing is positive, HPV mRNA testing may be recommended before more invasive procedures are recommended.

Testing for high-risk (oncogenic) HPV is summarized in Table 1. HPV is also the leading cause of oropharyngeal cancers; primarily the tonsils, tonsillar crypt, and the base of the tongue. HPV16 is the genotype most responsible and affects more males than females. While tabacco use is also a common cause of oropharyngeal cancer, the fastest growing segment of the oral and oropharyngeal cancer population are otherwise healthy, non smoking individuals in the 35-55 age range. Approximately 26 million Americans on any given day have an oral HPV infection detected in saliva or oral gargle samples. Of those, approximately only 1% are HPV16. The vast majority of individuals will clear the virus naturally through their own immune response, and never know that they were exposed or had it. Unlike cervical cancer, screening for oropharyngeal cancer is not cost effective.

Table1. American Cancer Society recommendations for cervical screening

Interfering factors

• Cervical specimens with low cellularity may diminish sensitivity of the test.

 • High concentrations of antifungal cream or contraceptive jelly may diminish sensitivity of the test.

 Procedure and patient care

 Before

* Explain the procedure for Pap smear.

* Instruct the patient not to douche or bathe in a tub during the 24 hours before the test.

* Instruct the patient to empty her bladder.

* Instruct the patient to reschedule testing if she is menstruating.

* Tell the patient that no fasting or sedation is required.

 During

 • Note the following procedural steps:

 1. The patient is placed in the lithotomy position.

 2. With the use of either a cytology brush or a wooden spat ula, a cervical mucous specimen is obtained by placing the instrument into the cervical os and rotating 3 to 5 times in clockwise and counterclockwise directions.

3. After specimen collection, rotate the broom-like device or spatula and Cytobrush several times in the collection vial to remove the specimen. Firmly cap the vial and discard the collection devices.

 4. Affix a patient identification label to the vial.

 5. Seal the vial and place in a plastic specimen bag along with a properly filled-out cytology requisition form and send them to the laboratory.

 • Note that a smear is obtained by a nurse or a physician in approximately 10 minutes.

* Tell the patient that no discomfort, except for insertion of the speculum, is associated with this procedure.

After

* Inform the patient that usually she will not be notified unless further evaluation is necessary.

*  Instruct the patient that HPV is a sexually transmitted disease. Proper precautions should be taken to prevent infecting sexual partners.

 Abnormal findings

 HPV infection

مواضيع ذات صلة

human T-cell lymphotropic virus (HTLV) I/II antibody

human placental lactogen (hPL, Human chorionic somatomammotropin [HCS])

human lymphocyte antigen B27 (HLA-B27 antigen, Human leukocyte A antigen, White blood cell antigens, Histocompatibility leukocyte A antigen)

Nucleic Acid –Based Tests

human chorionic gonadotropin (hCG, Pregnancy tests, hCG beta subunit)

homocysteine (Hcy)

HIV serologic and virologic testing

HIV RNA quantification (HIV viral load)

Molecules involved in Lipoprotein metabolism

Lipoproteins

Retinol Binding Protein

Direct Visualization Of The Organism