Renee Howell, PhD MLS(ASCP)

We demonstrate genotyping accuracy on a novel microfluidic platform with rapid serial PCR
and HSM. We used a microfluidic platform tailored to rapid serial PCR and high-speed melting (HSM) to genotype 4 single nucleotide variants. Two study sites each analyzed 100 samples for F2 (c.*97G?A), F5 (c.1601G?A), and MTHFR (c.665C?T and c.1286A?C) after blinding for genotype and genotype proportions. PCR and HSM were completed in a total of 12.5 min. Melting was performed at 0.5 °C/s. All… Show more

We demonstrate genotyping accuracy on a novel microfluidic platform with rapid serial PCR
and HSM. We used a microfluidic platform tailored to rapid serial PCR and high-speed melting (HSM) to genotype 4 single nucleotide variants. Two study sites each analyzed 100 samples for F2 (c.*97G?A), F5 (c.1601G?A), and MTHFR (c.665C?T and c.1286A?C) after blinding for genotype and genotype proportions. PCR and HSM were completed in a total of 12.5 min. Melting was performed at 0.5 °C/s. All samples were correctly genotyped by the instrument. Show less

A World Health Organization collaborative study was conducted to evaluate candidate international standards for human papillomavirus (HPV) Type 16 DNA (NIBSC code 06/202) and HPV Type 18 DNA (NIBSC code 06/206) for use in the amplification and detection steps of nucleic acid-based assays. The freeze-dried candidate international standards were prepared from bulk preparations of cloned plasmid containing full-length HPV-16 or HPV-18 genomic DNA. Nineteen laboratories from 13 countries… Show more

A World Health Organization collaborative study was conducted to evaluate candidate international standards for human papillomavirus (HPV) Type 16 DNA (NIBSC code 06/202) and HPV Type 18 DNA (NIBSC code 06/206) for use in the amplification and detection steps of nucleic acid-based assays. The freeze-dried candidate international standards were prepared from bulk preparations of cloned plasmid containing full-length HPV-16 or HPV-18 genomic DNA. Nineteen laboratories from 13 countries participated in the study using a variety of commercial and in-house quantitative and qualitative assays. The data presented here indicate that, upon freeze-drying, there is no significant loss in potency for the candidate HPV-18 DNA and a slight loss in potency for the candidate HPV-16 DNA; although this is likely not scientifically relevant when assay precision is considered. In general, the individual laboratory mean estimates for each study sample were grouped ±∼2 log10 around the theoretical HPV DNA concentration of the reconstituted ampoule (1 × 107 HPV genome equivalents/mL). The agreement between laboratories is improved when potencies are made relative to the candidate international standards, demonstrating their utility in harmonizing amplification and detection steps of HPV-16 and −18 DNA assays. Degradation studies indicate that the candidate international standards are extremely stable and suitable for long-term use. Based on these findings, the candidate standards were established as the 1st WHO international standards for HPV-16 DNA and HPV-18 DNA, each with a potency of 5 × 106 international units (IU) per ampoule or 1 × 107 IU mL−1 when reconstituted as directed. Show less

Cervical carcinoma is the most common cancer among Belizean women; however, data regarding the frequency of human papillomavirus (HPV) genotypes and their association with cervical cancer are nonexistent. We therefore included HPV genotyping as part of a week-long cervical cancer screening campaign conducted in Belize City in 2007. Conventional Papanicolaou smears with Hybrid Capture (HC) 2 HPV testing were performed on 463 women. All HC2-positive samples were genotyped using a developmental… Show more

Cervical carcinoma is the most common cancer among Belizean women; however, data regarding the frequency of human papillomavirus (HPV) genotypes and their association with cervical cancer are nonexistent. We therefore included HPV genotyping as part of a week-long cervical cancer screening campaign conducted in Belize City in 2007. Conventional Papanicolaou smears with Hybrid Capture (HC) 2 HPV testing were performed on 463 women. All HC2-positive samples were genotyped using a developmental GP5+/GP6+ polymerase chain reaction-coupled Luminex assay for 2 low-risk and 18 high-risk HPV types. The prevalence of high-risk HPV was 15.6% in the total population, 10.1% in those with normal cytologic findings, and 93.3% in women with a high-grade squamous intraepithelial lesion. Of patients with HPV infections, 35% had multiple types (5.4% of the total group). Of all women and of women with normal cytologic findings, 5.2% and 2.8%, respectively, had HPV16 or 18. For all women, HPV16, 18, 56, and 52 were present in decreasing order of frequency. HPV11 was present in only one patient, and none had HPV6. HPV16 was found in 47% of high-grade squamous epithelial lesions; however, no case of HSIL had HPV18 or 45. HPV35 and HPV58 were the next most common types in high-grade squamous intraepithelial lesion, each occurring in 20% of cases of high-grade squamous intraepithelial lesion, followed by HPV31 in 13.3%. Although women younger than 25 years old were underrepresented, these data suggest that the HPV profile of this cohort of Belizean women differs somewhat from that in the region. In addition, these data are of importance with regard to the development of HPV vaccines that will be used in less developed countries, where care should be taken not to implement vaccination at the cost of basic screening and diagnostic services. Show less