Comparison of diagnostic sensitivity and specificity of seven Cryptosporidium assays used in the UK

Chalmers, Rachel M.; Campbell, Brian; Crouch, Nigel; Charlett, André; Davies, Angharad

doi:10.1099/jmm.0.034181-0

Cited by 115 publications

(87 citation statements)

References 16 publications

(23 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The choice of diagnostic test depends on the number of specimens being tested, performance in local validation, available equipment and facilities, staff skills and training, time and cost considerations (Chalmers & Katzer, 2013). The diagnostic sensitivity and specificity of EIAs marketed in the UK have been shown to be similar to those provided by AP microscopy (Chalmers et al, 2011). EIAs have the advantage of being readily automated, enabling higher throughput than microscopy (Chalmers & Katzer, 2013).…”

Section: Resultsmentioning

confidence: 99%

“…1); pair-wise comparison showed that rates were significantly lower in laboratories using mZN compared with AP and EIA (Mann-Whitney U P50.03 and 0.04, respectively) while there was no significant difference between rates in laboratories using AP and EIA (Mann-Whitney U P50.645). The diagnostic sensitivity of mZN has been shown to be less than that of AP and EIA, and PCR has been shown to be most sensitive (Chalmers et al, 2011).…”

Section: Resultsmentioning

confidence: 99%

“…Thirteen of 85 (15 %) laboratories referred specimens to the national Cryptosporidium Reference Unit for confirmation of equivocal or borderline findings, amongst which those using EIA were over-represented (Table 2). Laboratories using EIA need to take steps to monitor performance, and receive guidance on the confirmation of positive reactions; the reference unit uses immunofluorescence microscopy (IFM), which is diagnostically and analytically sensitive and specific (Chalmers et al, 2011), simplifying the confirmation process. Although IFM is widely used in primary testing elsewhere (e.g.…”

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

An audit of the laboratory diagnosis of cryptosporidiosis in England and Wales

Chalmers

Atchison

Barlow

et al. 2015

Journal of Medical Microbiology

Self Cite

View full text Add to dashboard Cite

To assess the level of practice consistent with UK national standards for Cryptosporidium testing, an audit was performed of 156 publicly funded clinical microbiology laboratories in England and Wales between August 2013 and April 2014. Responses were received from 85 (54 %) laboratories. First line diagnostic methods used were mainly microscopy with modified Ziehl-Neelsen (mZN) or auramine phenol (AP) staining (68/85, 80 %), enzyme immunoassays (EIAs) (16/85, 19 %) or in-house PCR (1/85, 1 %). The use of EIAs was more widespread than reported previously. Various methods were used for confirmation of positive EIA reactions and laboratories frequently resorted to sending samples to the national reference laboratory for this purpose, indicating that guidance is required for performance monitoring and confirmation of positive reactions. Laboratory positivity rates were related to the diagnostic test used, with highest median rates reported by those using PCR, EIAs or AP microscopy, and the lowest by those using mZN microscopy. One-third of responding laboratories (28/85, 33 %) routinely tested all stools for Cryptosporidium. However, 16 (19 %) laboratories used stool consistency to decide whether to test for this parasite. Other selection criteria included patient age (n518; 21 % laboratories), history or clinical details (n540; 47 %), duration of hospitalization (n518; 21 %) or clinician requests (n525; 29 %). To encourage laboratories to test all stools submitted for the investigation of diarrhoeal illness for Cryptosporidium, revision of the guidance in the national standards is under way. This will enable improved assessment of the burden of illness and ability to monitor outbreaks, and measure changes in reported cases.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

An audit of the laboratory diagnosis of cryptosporidiosis in England and Wales

Chalmers

Atchison

Barlow

et al. 2015

Journal of Medical Microbiology

Self Cite

View full text Add to dashboard Cite

show abstract

“…A minimum confidence level of 95% was used for all statistical analyses. Estimates of real frequencies were made based on the sensitivity and specificity values of the auramine technique (sensitivity = 92.1%; specificity = 100%), as previously described by Chalmers et al (2011). The data were calculated based on the method described by Reiczigel et al (2010), using the EpiTools epidemiological calculators (SERGEANT, 2017).…”

Section: Methodsmentioning

confidence: 99%

Risk factors and infection due to Cryptosporidium spp. in dogs and cats in southern Rio Grande do Sul

Moreira

Baptista

Brasil

et al. 2018

Rev. Bras. Parasitol. Vet.

View full text Add to dashboard Cite

This study investigated the frequency of oocysts of Cryptosporidium spp. in feces from dogs and cats in five municipalities in the southern region of the state of Rio Grande do Sul. The risk factors associated with infection were also investigated. Feces samples from 110 dogs and 18 cats were stained using the auramine method. At the time of feces sampling, a questionnaire with semi-open-ended questions was applied to the animal guardians and all data obtained underwent statistical analysis. The real frequency of oocysts of Cryptosporidium spp. was 24.63% (27 dogs and two cats). Only four samples of dog feces were diarrheic and no presence of oocysts was observed in any of them. Variables that represented risk factors for infection were: homemade food, untreated water, circulation of animals on grassy terrain and living in the same environment as other animals (cattle). The results made it possible to inferring that within the population studied, the frequency of parasitism due to Cryptosporidium spp. in dogs was relevant and emphasize the asymptomatic nature of this infection. The adopting control measures are highlighted, particularly in relation to variables that represent risk factors for this infection.

show abstract

“…Laboratory methods for detecting Cryptosporidium were first based on microscopy in combination with various staining methods, the most widely used being the modified Ziehl-Neelsen staining method for oocysts, the sensitivity of which has been estimated at 75% (13,14). A direct fluorescent antibody assay (DFA) improved the sensitivity of conventional microscopy, as its sensitivity is about 1,000 oocysts per g of stool (15).…”

mentioning

confidence: 99%

Multicentric Evaluation of a New Real-Time PCR Assay for Quantification of Cryptosporidium spp. and Identification of Cryptosporidium parvum and Cryptosporidium hominis

et al. 2013

View full text Add to dashboard Cite

gCryptosporidium is a protozoan parasite responsible for gastroenteritis, especially in immunocompromised patients. Laboratory diagnosis of cryptosporidiosis relies on microscopy, antigen detection, and nucleic acid detection and analysis. Among the numerous molecular targets available, the 18S rRNA gene displays the best sensitivity and sequence variations between species and can be used for molecular typing assays. This paper presents a new real-time PCR assay for the detection and quantification of all Cryptosporidium species associated with the identification of Cryptosporidium hominis and Cryptosporidium parvum. The sensitivity and specificity of this new PCR assay were assessed on a multicentric basis, using well-characterized Cryptosporidiumpositive and -negative human stool samples, and the efficiencies of nine extraction methods were comparatively assessed using Cryptosporidium-seeded stool samples and phosphate-buffered saline samples. A comparison of extraction yields showed that the most efficient extraction method was the Boom technique in association with mechanical grinding, and column extraction showed higher binding capacity than extraction methods based on magnetic silica. Our PCR assay was able to quantify at least 300 oocysts per gram of stool. Satisfactory reproducibility between laboratories was observed. The two main species causing human disease, Cryptosporidium hominis and Cryptosporidium parvum, were identified using a duplex real-time PCR assay with specific TaqMan minor-groove-binding ligand (MGB) probes for the same amplicon. To conclude, this one-step quantitative PCR is well suited to the routine diagnosis of cryptosporidiosis since practical conditions, including DNA extraction, quantification using well-defined standards, and identification of the two main species infecting humans, have been positively assessed.

show abstract

Comparison of diagnostic sensitivity and specificity of seven Cryptosporidium assays used in the UK

Cited by 115 publications

References 16 publications

An audit of the laboratory diagnosis of cryptosporidiosis in England and Wales

An audit of the laboratory diagnosis of cryptosporidiosis in England and Wales

Risk factors and infection due to Cryptosporidium spp. in dogs and cats in southern Rio Grande do Sul

Multicentric Evaluation of a New Real-Time PCR Assay for Quantification of Cryptosporidium spp. and Identification of Cryptosporidium parvum and Cryptosporidium hominis

Contact Info

Product

Resources

About