| Test
7575 - HPV Genotyping |
| Method |
PCR and DNA Sequencing |
| Specimen
Requirements |
ThinPrep Solution: 2.0 ml (1.0 ml); SurePath Solution: 1.0 ml (0.5 ml);
Cervical Brush: Use Digene Cytology Brush Specimen Collection Kit, available from Genetic Assays. Cervical brush should be collected prior to the application of acetic acid if colposcopic examination is being performed;
Cervical Biopsy: 250 mg fresh tissue frozen in sterile saline solution or viral transport media;
Paraffin Embedded Tissue: Six quantity of 3 micron sections. |
| Collection
& Transport |
ThinPrep or SurePath Solution and Digene Cytology Brush Specimen Collection Kit: Ship at room temperature;
Cervical biopsy: Ship frozen in Styrofoam cooler with dry ice;
Paraffin Embedded Tissue: Ship at room temperature. |
| Causes
for Rejection |
ThinPrep: less than 1.0 ml and/or exceeds 3 months;
SurePath: less than 0.5 ml and/or exceeds 28 days;
Digene Cytology Brush Specimen Collect Kit received without a cervical brush or cervical brush collected after the application of acetic acid; |
| Specimen
Stability |
ThinPrep: stable up to 3 months at room temp;
SurePath: stable up to 28 days at room temp; Digene Cytology Brush Specimen Collect Kit: stable up to 14 days at room temp and indefinitely at -20ºC;
Cervical Biopsy: stable indefinitely at -20ºC;
Paraffin Embedded Tissue: stable indefinitely. |
| Reference
Range |
Not
Detected |
| TAT |
7-14
days |
| CPT
Code |
83907 Lysis of cells prior to nucleic acid extraction
83891 x 2 Isolation or extraction of highly purified nucleic acid
83894 x 2 Separation by gel electrophoresis
83909 Separation and Identification by high-resolution technique
83900 Amplification of patient nucleic acid, multiplex, 1st two sequences
83901 x 8 Amplification of patient nucleic acid, multiplex, each additional sequence
83904 Mutation identification by sequencing, single segment, each
83912 Interpretation and Report |
|
Clinical Utility
Of the 14 recognized high-risk types of HPV, type 16 and 18 are highly prevalent and are more oncogenic than other high risk types. Studies have shown that women infected with cervical HPV16 infections are at greater risk to developing CIN3+ compared to other high risk types. Women with normal cytology and HPV18 positive not only have an increased risk for CIN3+, but also adenocarcinoma. Additionally, HPV 33 , 45 and 58, which are much less prevalent than 16 and 18, have been reported in some studies as more oncogenic high-risk types.
Knowing a patient's HPV type provides clinicians with valuable information to guide follow up and treatment. A recent article in the Journal Gynecologic Oncology reviews the clinical utility of HPV genotyping. Women who are infected with the more oncogenic high-risk types and are cytology negative should be followed more closely. Several studies have demonstrated that cytology negative women that are positive for HPV16 or 18 are at greater risk of having or developing CIN3+ than women with LSIL cytology. A repeat pap smear to confirm both the cytology and HPV is probably in order. For women over 30 who repeatedly test positive for HPV16 or 18 but are cytology negative, more frequent follow-ups (6-12 months vs 2 years) may be warranted because of their higher risk for developing CIN-3+. |
