HHS Public Access Author manuscript Author Manuscript
Cancer. Author manuscript; available in PMC 2017 September 15. Published in final edited form as: Cancer. 2016 September 15; 122(18): 2836–2844. doi:10.1002/cncr.30123.
Accuracy of urinary human papillomavirus (HPV) testing for the presence of cervical HPVs and higher grades of cervical intraepithelial neoplasia Chandrika J Piyathilake, PhD1, Suguna Badiga, PhD1, Michelle M Chambers, MS1, Ilene Brill, MPH2, Roland Matthews, MD3, and Edward E Partridge, MD4
Author Manuscript
1The
University of Alabama at Birmingham (UAB) Department of Nutrition Sciences
2UAB
Department of Epidemiology
3Morehouse 4UAB
School of Medicine, Department of Obstetrics and Gynecology
Comprehensive Cancer Center
Abstract
Author Manuscript
Background—While urine based testing for human papillomavirus (HPV) is being explored as a practical approach for cervical cancer screening, whether the results differ by age, race and indicators of excess body weight or in populations exposed to HPV vaccines have not been documented by previous studies. The purpose of the study was to determine the accuracy of urinary HPV testing for presence of cervical HPVs and high grade cervical intraepithelial lesions (CIN 2 and 3) by the above stated population characteristics. Methods—Study population consisted of 502 women diagnosed with different grades of CIN. HPV testing was performed with paired urine and cervical cell DNA using Roche Diagnostics Linear Array. Agreement coefficient 1 (AC1) and probabilities were calculated to determine the accuracy of urinary HPV testing for the presence of cervical HPVs and CIN lesions. Results—We observed a substantial to almost perfect agreement (0.66–0.83) in the detection of any HPV genotype in urine compared to cervical specimens irrespective of population characteristics. Although the PPV for detection of CIN lesions was relatively low, the NPV for CIN 3 was high (≥ 90%) among women positive for any of the urinary or cervical HR-HPV genotypes or HPV genotypes not included in currently available HPV vaccines.
Author Manuscript
Conclusions—Our results demonstrated that urine HPV testing provides highly satisfactory results for excluding the possibility of having any cervical HPV infections, including HPV types
Correspondence to: Chandrika J Piyathilake, University of Alabama at Birmingham, Wallace Tumor Institute 420 D, 1824 6th Avenue South, Birmingham, AL 35294-3300, Phone: 205-975-5398 Fax: 205-934-7049 [email protected]. Conflict of interest: None Author’s contribution: Formulation of research goals and aims-CJP Generation of data and verification-MMC, CJP, SB Data analysis and interpretation-CJP, SB, IB Writing original draft and presentation of results-CJP, SB Review and editing of the final manuscript-CJP, SB, IB, MMC, RM, EEP
Piyathilake et al.
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Author Manuscript
not included in vaccines and CIN lesions associated with any HR-HPV regardless of woman’s age, race and excess body weight.
Precis The purpose of the study was to determine the accuracy of urinary HPV testing for presence of cervical HPVs and higher grade cervical intraepithelial lesions. Our results demonstrated that urine HPV testing provides highly satisfactory results for excluding the possibility of having any cervical HPV infections, including HPV types not included in vaccines and CIN lesions associated with any HR-HPV regardless of woman’s age, race and excess body weight.
Keywords cervix; urine; HPV; CIN; accuracy
Author Manuscript
Background
Author Manuscript Author Manuscript
Infection with carcinogenic or high risk human papillomaviruses (HR-HPVs), which are sexually transmitted, represent the most important risk factors for the development of cervical cancer (CC) as well as cervical intraepithelial neoplasia (CIN), precursor lesions for developing CC.1,2,3 More than 90% of CCs are associated with HR-HPV DNA.4 Studies that used improved HPV testing procedures have established HPV as a causative agent for CIN as well.5 Therefore, identification of women infected with HR-HPVs or with HR-HPV associated CIN lesions is of critical importance for preventing CC. Currently, CC is largely prevalent in the developing world where women are rarely screened for this disease. Testing for HPVs in samples other than cervical cells such as urine, a noninvasive and easy tocollect sample, could be more attractive to women because it bypasses medical examination, a significant barrier for women in the developing world because of socio-cultural or religious reasons. Further, urine HPV testing would offer a more cost effective option in lower-income countries that lack infrastructure for medical care. In developed countries such as in the USA, nearly 50% of CCs are found in women never screened, and an additional 10% of CCs occur among women not screened within the past five years.6,7 These observations suggest that it is important to understand the reasons for not receiving screening in this group of women. In developed countries, the body image disturbances may negatively affect preventive medical care such as screening for CC, not only because of avoiding screening care but also because of the difficulties in obtaining a proper sample such as pap smear if appropriate instruments such as a large vaginal specula is unavailable.8,9 Even though, testing for HPV in urine may be more acceptable in this situation, the possibility of this approach has never been evaluated. Since studies have documented that African American (AA) women are more satisfied with their bodies than are their Caucasian American (CA) counterparts10, it is also important to understand whether the accuracy of urinary HPV testing for the presence of cervical HPVs differ by race. Currently there are three main ways to prevent CC, namely, HPV vaccination to prevent infection, continue to monitor vaccinated women for risk associated with non-vaccine HPV genotypes and screening of women already infected with HPVs to detect the disease at an earlier stage, when it is easier to prevent the progression of lesions. Since currently available Cancer. Author manuscript; available in PMC 2017 September 15.
Piyathilake et al.
Page 3
Author Manuscript
prophylactic HPV vaccines (bivalent, quadrivalent and 9-valent) do not provide complete protection against HPVs, HPV-based screening tests are still needed in the management of vaccinated individuals who may get exposed to HPV genotypes not included in vaccines and develop CIN lesions associated with those HPV genotypes. A urine HPV test rather than a cervical HPV test would be more acceptable and cost-effective for this population as well.
Author Manuscript
A recent meta-analysis reported that the detection of HPV DNA in urine has good accuracy for the presence of cervical HPVs.11 This meta-analysis was unable to derive the accuracy of CIN prediction as only two studies reported relevant data.12 None of these previous studies have adequately evaluated whether the accuracy of urinary HPV testing for the presence of cervical HPVs differ by race or by indicators of excess body weight. Further, there are no reports on whether the prevalence of CIN lesions differ based on the presence of HPV genotypes detected in cervical vs. urine in a non-vaccinated or a vaccinated population. In addition, even though HPV testing has been approved by the FDA for primary screening of ≥25 year old females, no studies have evaluated whether the accuracy of urinary HPV testing for the presence of cervical HPVs differs by this age cut point.
Author Manuscript
Based on this background, the purpose of the study was to 1) determine HPV genotypes in paired specimens of cervical and urinary cell DNA and test the overall accuracy of urinary HPV testing for the presence of cervical HPVs and evaluate whether the accuracy differs by age, race, indicators of excess body weight (body mass index [BMI] and % body fat [%BF]) and CIN status; 2) determine whether the positive predictive value (PPV) and negative predictive value (NPV) of detecting CIN lesions differ based on the presence of HPV genotypes detected in cervical vs. urine and evaluate whether the results differ by age, race and by indicators of excess body weight; 3) determine whether the concordance between urine and cervical HPV genotypes differ if the currently available HPV prophylactic vaccines are effective in preventing those infections and 4) determine whether PPV and NPV of detecting CIN lesions differ based on the presence of HPV genotypes detected in cervical vs. urine if the currently available HPV prophylactic vaccines are effective in preventing those infections.
Methods Study Population
Author Manuscript
The study population (N=502) included women enrolled by two studies funded by the National Cancer Institute (NCI) (R01CA105448 and R01CA102489). All women were diagnosed with abnormal cervical cells in clinics of the Health Departments in Jefferson County and surrounding counties in Alabama and were referred to the University of Alabama at Birmingham (UAB) for further examination by colposcopy. Women were 19–50 years old, had no history of CC or other cancer of the lower genital tract, no history of hysterectomy or destructive therapy of the cervix; were not pregnant, and were not using anti-folate medications. Based on Roche Diagnostics Linear Array, 63% and 37% were positive and negative for any HR-HPV in cervical samples, respectively. The distribution of CIN diagnosis of the population is the following: 106 women were diagnosed with CIN 2+ (cases, including CIN 2 [n=72], CIN 3 [n=34]) and 396 women were diagnosed with ≤ CIN 1 (non-cases, including normal cervical epithelium [n=23], HPV cytopathic effect [HCE, Cancer. Author manuscript; available in PMC 2017 September 15.
Piyathilake et al.
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Author Manuscript
n=40], reactive nuclear enlargement [RNE, n=73] or CIN 1 [n=260]). The BMI was calculated using the height and weight measurements (weight kg/[height m]2). Height and weight measurements were obtained using standard protocols by the study personnel, reducing the potential for BMI misclassification compared with self-report. The % BF was measured using a TANITA-bioelectrical impedance analysis instrument (Model TBF-300A) and summarized as two categories, ≤ 33% or > 33%. The study protocols and procedures were approved by the UAB Institutional Review Board. Urine samples were collected before the collection of cervical cells. Exfoliated cervical cells collected with a cervical brush and immediately rinsed in 10 mL of PBS were kept cold until transported to the laboratory on ice within 2 hours of collection. In the laboratory, both cervical cell and urine samples were centrifuged and the resulting pellets were stored at −20°C until HPV detection assays were performed.
Author Manuscript
Detection and determination of HPV genotypes DNA was extracted from cervical and urine cell pellets using the QIAamp MiniElute Media kit (Qiagen, Inc.) following the manufacturer’s instructions. HPV genotyping test (Linear array; Roche Diagnostics) was performed according to the manufacturer's instructions by a research associate trained by personnel from Roche Diagnostics. Briefly, target DNA was amplified by PCR using the PGMY09/11 L1 consensus primer system that included coamplification of a human cellular target, β-globin that served as an internal control for adequate sample cellularity and extraction.
Author Manuscript
Detection and HPV genotyping were achieved using a reverse line-blot method, and this test included probes for 37 anogenital HPV genotypes [6, 11, 16, 18, 26, 31, 33, 35, 39, 40, 42, 45, 51, 52, 53, 54, 55, 56, 58, 59, 61, 62, 64, 66, 67, 68, 69, 70, 71, 72, 73 (MM9), 81, 82 (MM4), 83 (MM7), 84 (MM8), IS39, and CP6108]. HPV 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, and 68 were considered as HR-HPV genotypes and all other types as low risk HPV genotypes in this analysis. Data Analysis
Author Manuscript
The differences in the demographic characteristics between cases and non-cases were tested using Chi-square test. We calculated the detection rate of HPV genotypes (any HPV, any HR-HPV and HPV 16 or 18) by diagnosis in paired specimens of cervical and urinary cell DNA and used McNemar’s test to determine the differences between paired proportions. The overall accuracy of urinary HPV testing for the presence of cervical HPVs was evaluated by using agreement statistics which included crude concordance, and the agreement coefficient 1 (AC1)13. AC1 rather than Cohen’s kappa, a commonly used measure of agreement, was used in our analysis because kappa is sensitive to uneven distributions of the categories. The presence of uneven category distributions, often the case with observational data such as ours can potentially result in a so-called kappa “paradox”14 where high crude agreement is associated to low or even negative kappa values. The AC1 statistic is an alternative that differs from kappa in the way chance agreement is computed and may be a more robust indicator of chance-corrected agreement with uneven distributions of categories. In our analysis, we have defined the degree of agreement based on the categorization as proposed by Landis and Koch15 < 0 no agreement, 0.01 to 0.2 slight
Cancer. Author manuscript; available in PMC 2017 September 15.
Piyathilake et al.
Page 5
Author Manuscript
agreement, 0.21 to 0.40 fair agreement, 0.41 to 0.60 moderate agreement, 0.61 to 0.80 substantial agreement and 0.8 to 1.0 almost perfect agreement. All analyses were performed in the entire population and by categories of age (< 25 years and ≥ 25 years), race (CA and AA), indicators of excess body weight (BMI, < 25 kg/m2 and ≥ 25 kg/m2; % BF, < 33% and ≥ 33%) and case status (non-cases [≤ CIN 1] and cases [CIN 2+]). We determined the PPV, the probability of the presence of higher grade CIN lesions (CIN 2 or 3) when positive for any HR-HPV and the negative predictive value (NPV), the probability of the absence of CIN 2 or 3 when negative for any HR-HPV using HR-HPV genotype results of urine and cervical specimens in the entire population and by categories of age, race and indicators of excess body weight. The interpretation of PPV and NPV was based on a preset categorization scheme (≥ 90 high, ≥ 80-
Cancer. Author manuscript; available in PMC 2017 September 15. Published in final edited form as: Cancer. 2016 September 15; 122(18): 2836–2844. doi:10.1002/cncr.30123.
Accuracy of urinary human papillomavirus (HPV) testing for the presence of cervical HPVs and higher grades of cervical intraepithelial neoplasia Chandrika J Piyathilake, PhD1, Suguna Badiga, PhD1, Michelle M Chambers, MS1, Ilene Brill, MPH2, Roland Matthews, MD3, and Edward E Partridge, MD4
Author Manuscript
1The
University of Alabama at Birmingham (UAB) Department of Nutrition Sciences
2UAB
Department of Epidemiology
3Morehouse 4UAB
School of Medicine, Department of Obstetrics and Gynecology
Comprehensive Cancer Center
Abstract
Author Manuscript
Background—While urine based testing for human papillomavirus (HPV) is being explored as a practical approach for cervical cancer screening, whether the results differ by age, race and indicators of excess body weight or in populations exposed to HPV vaccines have not been documented by previous studies. The purpose of the study was to determine the accuracy of urinary HPV testing for presence of cervical HPVs and high grade cervical intraepithelial lesions (CIN 2 and 3) by the above stated population characteristics. Methods—Study population consisted of 502 women diagnosed with different grades of CIN. HPV testing was performed with paired urine and cervical cell DNA using Roche Diagnostics Linear Array. Agreement coefficient 1 (AC1) and probabilities were calculated to determine the accuracy of urinary HPV testing for the presence of cervical HPVs and CIN lesions. Results—We observed a substantial to almost perfect agreement (0.66–0.83) in the detection of any HPV genotype in urine compared to cervical specimens irrespective of population characteristics. Although the PPV for detection of CIN lesions was relatively low, the NPV for CIN 3 was high (≥ 90%) among women positive for any of the urinary or cervical HR-HPV genotypes or HPV genotypes not included in currently available HPV vaccines.
Author Manuscript
Conclusions—Our results demonstrated that urine HPV testing provides highly satisfactory results for excluding the possibility of having any cervical HPV infections, including HPV types
Correspondence to: Chandrika J Piyathilake, University of Alabama at Birmingham, Wallace Tumor Institute 420 D, 1824 6th Avenue South, Birmingham, AL 35294-3300, Phone: 205-975-5398 Fax: 205-934-7049 [email protected]. Conflict of interest: None Author’s contribution: Formulation of research goals and aims-CJP Generation of data and verification-MMC, CJP, SB Data analysis and interpretation-CJP, SB, IB Writing original draft and presentation of results-CJP, SB Review and editing of the final manuscript-CJP, SB, IB, MMC, RM, EEP
Piyathilake et al.
Page 2
Author Manuscript
not included in vaccines and CIN lesions associated with any HR-HPV regardless of woman’s age, race and excess body weight.
Precis The purpose of the study was to determine the accuracy of urinary HPV testing for presence of cervical HPVs and higher grade cervical intraepithelial lesions. Our results demonstrated that urine HPV testing provides highly satisfactory results for excluding the possibility of having any cervical HPV infections, including HPV types not included in vaccines and CIN lesions associated with any HR-HPV regardless of woman’s age, race and excess body weight.
Keywords cervix; urine; HPV; CIN; accuracy
Author Manuscript
Background
Author Manuscript Author Manuscript
Infection with carcinogenic or high risk human papillomaviruses (HR-HPVs), which are sexually transmitted, represent the most important risk factors for the development of cervical cancer (CC) as well as cervical intraepithelial neoplasia (CIN), precursor lesions for developing CC.1,2,3 More than 90% of CCs are associated with HR-HPV DNA.4 Studies that used improved HPV testing procedures have established HPV as a causative agent for CIN as well.5 Therefore, identification of women infected with HR-HPVs or with HR-HPV associated CIN lesions is of critical importance for preventing CC. Currently, CC is largely prevalent in the developing world where women are rarely screened for this disease. Testing for HPVs in samples other than cervical cells such as urine, a noninvasive and easy tocollect sample, could be more attractive to women because it bypasses medical examination, a significant barrier for women in the developing world because of socio-cultural or religious reasons. Further, urine HPV testing would offer a more cost effective option in lower-income countries that lack infrastructure for medical care. In developed countries such as in the USA, nearly 50% of CCs are found in women never screened, and an additional 10% of CCs occur among women not screened within the past five years.6,7 These observations suggest that it is important to understand the reasons for not receiving screening in this group of women. In developed countries, the body image disturbances may negatively affect preventive medical care such as screening for CC, not only because of avoiding screening care but also because of the difficulties in obtaining a proper sample such as pap smear if appropriate instruments such as a large vaginal specula is unavailable.8,9 Even though, testing for HPV in urine may be more acceptable in this situation, the possibility of this approach has never been evaluated. Since studies have documented that African American (AA) women are more satisfied with their bodies than are their Caucasian American (CA) counterparts10, it is also important to understand whether the accuracy of urinary HPV testing for the presence of cervical HPVs differ by race. Currently there are three main ways to prevent CC, namely, HPV vaccination to prevent infection, continue to monitor vaccinated women for risk associated with non-vaccine HPV genotypes and screening of women already infected with HPVs to detect the disease at an earlier stage, when it is easier to prevent the progression of lesions. Since currently available Cancer. Author manuscript; available in PMC 2017 September 15.
Piyathilake et al.
Page 3
Author Manuscript
prophylactic HPV vaccines (bivalent, quadrivalent and 9-valent) do not provide complete protection against HPVs, HPV-based screening tests are still needed in the management of vaccinated individuals who may get exposed to HPV genotypes not included in vaccines and develop CIN lesions associated with those HPV genotypes. A urine HPV test rather than a cervical HPV test would be more acceptable and cost-effective for this population as well.
Author Manuscript
A recent meta-analysis reported that the detection of HPV DNA in urine has good accuracy for the presence of cervical HPVs.11 This meta-analysis was unable to derive the accuracy of CIN prediction as only two studies reported relevant data.12 None of these previous studies have adequately evaluated whether the accuracy of urinary HPV testing for the presence of cervical HPVs differ by race or by indicators of excess body weight. Further, there are no reports on whether the prevalence of CIN lesions differ based on the presence of HPV genotypes detected in cervical vs. urine in a non-vaccinated or a vaccinated population. In addition, even though HPV testing has been approved by the FDA for primary screening of ≥25 year old females, no studies have evaluated whether the accuracy of urinary HPV testing for the presence of cervical HPVs differs by this age cut point.
Author Manuscript
Based on this background, the purpose of the study was to 1) determine HPV genotypes in paired specimens of cervical and urinary cell DNA and test the overall accuracy of urinary HPV testing for the presence of cervical HPVs and evaluate whether the accuracy differs by age, race, indicators of excess body weight (body mass index [BMI] and % body fat [%BF]) and CIN status; 2) determine whether the positive predictive value (PPV) and negative predictive value (NPV) of detecting CIN lesions differ based on the presence of HPV genotypes detected in cervical vs. urine and evaluate whether the results differ by age, race and by indicators of excess body weight; 3) determine whether the concordance between urine and cervical HPV genotypes differ if the currently available HPV prophylactic vaccines are effective in preventing those infections and 4) determine whether PPV and NPV of detecting CIN lesions differ based on the presence of HPV genotypes detected in cervical vs. urine if the currently available HPV prophylactic vaccines are effective in preventing those infections.
Methods Study Population
Author Manuscript
The study population (N=502) included women enrolled by two studies funded by the National Cancer Institute (NCI) (R01CA105448 and R01CA102489). All women were diagnosed with abnormal cervical cells in clinics of the Health Departments in Jefferson County and surrounding counties in Alabama and were referred to the University of Alabama at Birmingham (UAB) for further examination by colposcopy. Women were 19–50 years old, had no history of CC or other cancer of the lower genital tract, no history of hysterectomy or destructive therapy of the cervix; were not pregnant, and were not using anti-folate medications. Based on Roche Diagnostics Linear Array, 63% and 37% were positive and negative for any HR-HPV in cervical samples, respectively. The distribution of CIN diagnosis of the population is the following: 106 women were diagnosed with CIN 2+ (cases, including CIN 2 [n=72], CIN 3 [n=34]) and 396 women were diagnosed with ≤ CIN 1 (non-cases, including normal cervical epithelium [n=23], HPV cytopathic effect [HCE, Cancer. Author manuscript; available in PMC 2017 September 15.
Piyathilake et al.
Page 4
Author Manuscript
n=40], reactive nuclear enlargement [RNE, n=73] or CIN 1 [n=260]). The BMI was calculated using the height and weight measurements (weight kg/[height m]2). Height and weight measurements were obtained using standard protocols by the study personnel, reducing the potential for BMI misclassification compared with self-report. The % BF was measured using a TANITA-bioelectrical impedance analysis instrument (Model TBF-300A) and summarized as two categories, ≤ 33% or > 33%. The study protocols and procedures were approved by the UAB Institutional Review Board. Urine samples were collected before the collection of cervical cells. Exfoliated cervical cells collected with a cervical brush and immediately rinsed in 10 mL of PBS were kept cold until transported to the laboratory on ice within 2 hours of collection. In the laboratory, both cervical cell and urine samples were centrifuged and the resulting pellets were stored at −20°C until HPV detection assays were performed.
Author Manuscript
Detection and determination of HPV genotypes DNA was extracted from cervical and urine cell pellets using the QIAamp MiniElute Media kit (Qiagen, Inc.) following the manufacturer’s instructions. HPV genotyping test (Linear array; Roche Diagnostics) was performed according to the manufacturer's instructions by a research associate trained by personnel from Roche Diagnostics. Briefly, target DNA was amplified by PCR using the PGMY09/11 L1 consensus primer system that included coamplification of a human cellular target, β-globin that served as an internal control for adequate sample cellularity and extraction.
Author Manuscript
Detection and HPV genotyping were achieved using a reverse line-blot method, and this test included probes for 37 anogenital HPV genotypes [6, 11, 16, 18, 26, 31, 33, 35, 39, 40, 42, 45, 51, 52, 53, 54, 55, 56, 58, 59, 61, 62, 64, 66, 67, 68, 69, 70, 71, 72, 73 (MM9), 81, 82 (MM4), 83 (MM7), 84 (MM8), IS39, and CP6108]. HPV 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, and 68 were considered as HR-HPV genotypes and all other types as low risk HPV genotypes in this analysis. Data Analysis
Author Manuscript
The differences in the demographic characteristics between cases and non-cases were tested using Chi-square test. We calculated the detection rate of HPV genotypes (any HPV, any HR-HPV and HPV 16 or 18) by diagnosis in paired specimens of cervical and urinary cell DNA and used McNemar’s test to determine the differences between paired proportions. The overall accuracy of urinary HPV testing for the presence of cervical HPVs was evaluated by using agreement statistics which included crude concordance, and the agreement coefficient 1 (AC1)13. AC1 rather than Cohen’s kappa, a commonly used measure of agreement, was used in our analysis because kappa is sensitive to uneven distributions of the categories. The presence of uneven category distributions, often the case with observational data such as ours can potentially result in a so-called kappa “paradox”14 where high crude agreement is associated to low or even negative kappa values. The AC1 statistic is an alternative that differs from kappa in the way chance agreement is computed and may be a more robust indicator of chance-corrected agreement with uneven distributions of categories. In our analysis, we have defined the degree of agreement based on the categorization as proposed by Landis and Koch15 < 0 no agreement, 0.01 to 0.2 slight
Cancer. Author manuscript; available in PMC 2017 September 15.
Piyathilake et al.
Page 5
Author Manuscript
agreement, 0.21 to 0.40 fair agreement, 0.41 to 0.60 moderate agreement, 0.61 to 0.80 substantial agreement and 0.8 to 1.0 almost perfect agreement. All analyses were performed in the entire population and by categories of age (< 25 years and ≥ 25 years), race (CA and AA), indicators of excess body weight (BMI, < 25 kg/m2 and ≥ 25 kg/m2; % BF, < 33% and ≥ 33%) and case status (non-cases [≤ CIN 1] and cases [CIN 2+]). We determined the PPV, the probability of the presence of higher grade CIN lesions (CIN 2 or 3) when positive for any HR-HPV and the negative predictive value (NPV), the probability of the absence of CIN 2 or 3 when negative for any HR-HPV using HR-HPV genotype results of urine and cervical specimens in the entire population and by categories of age, race and indicators of excess body weight. The interpretation of PPV and NPV was based on a preset categorization scheme (≥ 90 high, ≥ 80-
