Mary McMenamin1, Michael McKenna. 1. Cytopathology Department, Altnagelvin Hospital, Western Health and Social Care Trust, Londonderry, Northern Ireland, United Kingdom.
Abstract
BACKGROUND: The authors previously demonstrated that lysing samples with glacial acetic acid (GAA) before human papillomavirus (HPV) testing does not adversely affect HPV detection with the cobas 4800 HPV Test. However, the long-term impact of GAA on HPV DNA was not explored in that study, and inherent cell loss with the lysing protocol used also was observed. The current study considered the long-term effects of GAA treatment of cervical ThinPrep samples on HPV detection with the cobas 4800 HPV Test. They also modified the manufacturer's lysing procedure for ThinPrep specimens to help prevent cell loss. METHODS: Seventy-eight ThinPrep samples, including previously lysed, archived specimens, were split; then, 1 part was treated with GAA according to the manufacturer's protocol or using a modified protocol, and the other part was left untreated. All samples were tested for HPV using the cobas 4800 HPV Test. The HPV-positive/HPV-negative status of tested samples was used to determine the level of agreement between treated and untreated fractions. Performance of the modified lysing procedure was assessed relative to the manufacturer's protocol. RESULTS: Positive HPV status produced 97% agreement between the GAA-treated/untreated fractions. Concordance between the GAA-treated/untreated fractions did not differ between the 2 lysing methods; however, the average percentage increases in β-globin and HPV cycle threshold values after lysing were less discernible for the modified lysing method. CONCLUSIONS: GAA treatment of cervical ThinPrep specimens does not have long-term adverse effects on HPV detection with the cobas 4800 HPV Test. The manufacturer's GAA lysing procedure for ThinPrep specimens can be reliably modified for specimens that may subsequently undergo HPV testing.
BACKGROUND: The authors previously demonstrated that lysing samples with glacial acetic acid (GAA) before human papillomavirus (HPV) testing does not adversely affect HPV detection with the cobas 4800 HPV Test. However, the long-term impact of GAA on HPV DNA was not explored in that study, and inherent cell loss with the lysing protocol used also was observed. The current study considered the long-term effects of GAA treatment of cervical ThinPrep samples on HPV detection with the cobas 4800 HPV Test. They also modified the manufacturer's lysing procedure for ThinPrep specimens to help prevent cell loss. METHODS: Seventy-eight ThinPrep samples, including previously lysed, archived specimens, were split; then, 1 part was treated with GAA according to the manufacturer's protocol or using a modified protocol, and the other part was left untreated. All samples were tested for HPV using the cobas 4800 HPV Test. The HPV-positive/HPV-negative status of tested samples was used to determine the level of agreement between treated and untreated fractions. Performance of the modified lysing procedure was assessed relative to the manufacturer's protocol. RESULTS: Positive HPV status produced 97% agreement between the GAA-treated/untreated fractions. Concordance between the GAA-treated/untreated fractions did not differ between the 2 lysing methods; however, the average percentage increases in β-globin and HPV cycle threshold values after lysing were less discernible for the modified lysing method. CONCLUSIONS:GAA treatment of cervical ThinPrep specimens does not have long-term adverse effects on HPV detection with the cobas 4800 HPV Test. The manufacturer's GAA lysing procedure for ThinPrep specimens can be reliably modified for specimens that may subsequently undergo HPV testing.