'Fit-for-purpose?' - challenges and opportunities for applications of blockchain technology in the future of healthcare

Blockchain is a shared distributed digital ledger technology that can better facilitate data management, provenance and security, and has the potential to transform healthcare. Importantly, blockchain represents a data architecture, whose application goes far beyond Bitcoin - the cryptocurrency that relies on blockchain and has popularized the technology. In the health sector, blockchain is being aggressively explored by various stakeholders to optimize business processes, lower costs, improve patient outcomes, enhance compliance, and enable better use of healthcare-related data. However, critical in assessing whether blockchain can fulfill the hype of a technology characterized as 'revolutionary' and 'disruptive', is the need to ensure that blockchain design elements consider actual healthcare needs from the diverse perspectives of consumers, patients, providers, and regulators. In addition, answering the real needs of healthcare stakeholders, blockchain approaches must also be responsive to the unique challenges faced in healthcare compared to other sectors of the economy. In this sense, ensuring that a health blockchain is 'fit-for-purpose' is pivotal. This concept forms the basis for this article, where we share views from a multidisciplinary group of practitioners at the forefront of blockchain conceptualization, development, and deployment.

Periorbital erythema and swelling as a presenting sign of lupus erythematosus in tertiary referral centers and literature review

Background Cutaneous lupus erythematosus (CLE) includes a broad range of dermatologic manifestations. Periorbital involvement, however, is a relatively rare clinical presentation of CLE. Objectives This clinical study aimed to investigate the characteristics of this unique presentation of CLE in tertiary medical centers. Methods We enrolled patients with periorbital erythema and swelling as the presenting sign of lupus erythematosus, from January 2003 to November 2017, using the data of 553 pathologically proven CLE cases from the registration database of the Chang Gung Memorial Hospitals in Taiwan. Results We enrolled a total of 25 patients. The mean age was 46.7 years and 68% of the patients were female. Most of the patients (84.0%) presented with unilateral involvement, with the left orbit involved in 15 patients (60%); the upper eyelid was the most frequently involved (72%). Mean duration between the onset of clinical manifestations and the diagnosis of CLE was approximately 59 weeks. Nineteen patients had been previously misdiagnosed. All patients had features compatible with CLE on histopathological examination. In contrast, laboratory analysis of the autoimmune profile often revealed negative results, including those for antinuclear antibodies (25%). Notably, anti-SSA/SSB (45.5%) showed the highest positive rate. During follow-up, six patients developed systemic lupus erythematosus (SLE) and two patients developed Sjögren syndrome. Conclusions The diagnosis of CLE presenting as periorbital erythema and swelling is often delayed because of clinical mimicry and the high proportion of negative results on autoantibody tests. Increased clinical suspicion and prompt histopathological examination are crucial for early diagnosis. Moreover, one-fourth of the patients ultimately developed SLE, which highlights the importance of clinical awareness.

Identifying and characterizing highly similar notes in big clinical note datasets

BACKGROUND

Big clinical note datasets found in electronic health records (EHR) present substantial opportunities to train accurate statistical models that identify patterns in patient diagnosis and outcomes. However, near-to-exact duplication in note texts is a common issue in many clinical note datasets. We aimed to use a scalable algorithm to de-duplicate notes and further characterize the sources of duplication.

METHODS

We use an approximation algorithm to minimize pairwise comparisons consisting of three phases: (1) Minhashing with Locality Sensitive Hashing; (2) a clustering method using tree-structured disjoint sets; and (3) classification of near-duplicates (exact copies, common machine output notes, or similar notes) via pairwise comparison of notes in each cluster. We use the Jaccard Similarity (JS) to measure similarity between two documents. We analyzed two big clinical note datasets: our institutional dataset and MIMIC-III.

RESULTS

There were 1,528,940 notes analyzed from our institution. The de-duplication algorithm completed in 36.3 h. When the JS threshold was set at 0.7, the total number of clusters was 82,371 (total notes = 304,418). Among all JS thresholds, no clusters contained pairs of notes that were incorrectly clustered. When the JS threshold was set at 0.9 or 1.0, the de-duplication algorithm captured 100% of all random pairs with their JS at least as high as the set thresholds from the validation set. Similar performance was noted when analyzing the MIMIC-III dataset.

CONCLUSIONS

We showed that among the EHR from our institution and from the publicly-available MIMIC-III dataset, there were a significant number of near-to-exact duplicated notes.

Blockchain distributed ledger technologies for biomedical and health care applications

Objectives

To introduce blockchain technologies, including their benefits, pitfalls, and the latest applications, to the biomedical and health care domains.

Target Audience

Biomedical and health care informatics researchers who would like to learn about blockchain technologies and their applications in the biomedical/health care domains.

Scope

The covered topics include: (1) introduction to the famous Bitcoin crypto-currency and the underlying blockchain technology; (2) features of blockchain; (3) review of alternative blockchain technologies; (4) emerging nonfinancial distributed ledger technologies and applications; (5) benefits of blockchain for biomedical/health care applications when compared to traditional distributed databases; (6) overview of the latest biomedical/health care applications of blockchain technologies; and (7) discussion of the potential challenges and proposed solutions of adopting blockchain technologies in biomedical/health care domains.

Ensembles of NLP Tools for Data Element Extraction from Clinical Notes

Natural Language Processing (NLP) is essential for concept extraction from narrative text in electronic health records (EHR). To extract numerous and diverse concepts, such as data elements (i.e., important concepts related to a certain medical condition), a plausible solution is to combine various NLP tools into an ensemble to improve extraction performance. However, it is unclear to what extent ensembles of popular NLP tools improve the extraction of numerous and diverse concepts. Therefore, we built an NLP ensemble pipeline to synergize the strength of popular NLP tools using seven ensemble methods, and to quantify the improvement in performance achieved by ensembles in the extraction of data elements for three very different cohorts. Evaluation results show that the pipeline can improve the performance of NLP tools, but there is high variability depending on the cohort.

Finding Related Publications: Extending the Set of Terms Used to Assess Article Similarity

Recommendation of related articles is an important feature of the PubMed. The PubMed Related Citations (PRC) algorithm is the engine that enables this feature, and it leverages information on 22 million citations. We analyzed the performance of the PRC algorithm on 4584 annotated articles from the 2005 Text REtrieval Conference (TREC) Genomics Track data. Our analysis indicated that the PRC highest weighted term was not always consistent with the critical term that was most directly related to the topic of the article. We implemented term expansion and found that it was a promising and easy-to-implement approach to improve the performance of the PRC algorithm for the TREC 2005 Genomics data and for the TREC 2014 Clinical Decision Support Track data. For term expansion, we trained a Skip-gram model using the Word2Vec package. This extended PRC algorithm resulted in higher average precision for a large subset of articles. A combination of both algorithms may lead to improved performance in related article recommendations.

Weakly supervised learning of biomedical information extraction from curated data

Background

Numerous publicly available biomedical databases derive data by curating from literatures. The curated data can be useful as training examples for information extraction, but curated data usually lack the exact mentions and their locations in the text required for supervised machine learning. This paper describes a general approach to information extraction using curated data as training examples. The idea is to formulate the problem as cost-sensitive learning from noisy labels, where the cost is estimated by a committee of weak classifiers that consider both curated data and the text.

Results

We test the idea on two information extraction tasks of Genome-Wide Association Studies (GWAS). The first task is to extract target phenotypes (diseases or traits) of a study and the second is to extract ethnicity backgrounds of study subjects for different stages (initial or replication). Experimental results show that our approach can achieve 87 % of Precision-at-2 (P@2) for disease/trait extraction, and 0.83 of F1-Score for stage-ethnicity extraction, both outperforming their cost-insensitive baseline counterparts.

Conclusions

The results show that curated biomedical databases can potentially be reused as training examples to train information extractors without expert annotation or refinement, opening an unprecedented opportunity of using “big data” in biomedical text mining.

Electronic supplementary material

The online version of this article (doi:10.1186/s12859-015-0844-1) contains supplementary material, which is available to authorized users.

Learning to improve area-under-FROC for imbalanced medical data classification using an ensemble method

This paper presents our solution for KDD Cup 2008 competition that aims at optimizing the area under ROC for breast cancer detection. We exploited weighted-based classification mechanism to improve the accuracy of patient classification (each patient is represented by a collection of data points). Final predictions for challenge 1 are generated by combining outputs from weighted SVM and AdaBoost; whereas we integrate SVM, AdaBoost, and GA to produce the results for challenge 2. We have also tried location-based classification and model adaptation to add the testing data into training. Our results outperform other participants given the same set of features, and was selected as the joint winner in KDD Cup 2008.

Neolysogenization of Xanthomonas campestris pv. citri infected with filamentous phage Cf16

All previously described filamentous bacteriophages are capable of persistent infection while their DNA replicates as an episome in the host cell. Filamentous phage Cf16 undergoes an infectious cycle different from other filamentous phages reported heretofore. Upon initial infection with Cf16, infective centers are formed, each of which produces a large number of phage particles. As the infectious cycle progresses, the phage particles released and infective centers formed per carrier cell decrease with time. Finally, the Cf16 enters a "prophage" state, in which the carrier cell becomes lysogenic containing only one complete phage genome in an integrated form. One out of 10(3)-10(6) lysogenic cells can develop spontaneously into an infective center, which releases only one to two phage particles per cell in stationary phase culture. After infection, the Cf16 genome integrates into the host chromosome and replicates as a part of it. Free RF (replicative form) coexists with the integrated form and replicates independently from host chromosome. Upon further division, carrier cells eliminate the free RF at each succeeding generation. When Cf16 reaches the "prophage" state, only the integrated phage genome remains in the carrier cell with no detectable free RF.

The lysogenic cycle of the filamentous phage Cflt from Xanthomonas campestris pv. citri

A phage, Cflt, forming turbid plaques, was isolated from Xanthomonas campestris pv. citri. After infection, infected sensitive cells become immune to Cflt and produce very few phages. These properties were genetically rather stable. The phage was purified and shown to be filamentous with a size of 1157 +/- 73 nm. The genome size is about 7.62 kb. The phage does not affect the growth of host bacteria. Under natural cultivation conditions Cflt-lysogenized cells could be induced spontaneously to give high phage yields, or cured to give phage-free cells. The integration of Cflt DNA into host DNA was proved by Southern blot hybridization. The lysogenic phage was genetically stable in log phase cells and persisted in stationary phase cells through many cell generations in the absence of extracellular phage reinfection.

Intraductal papillary neoplasia of the liver associated with hepatolithiasis

Intraductal papillary growth of neoplastic biliary epithelia with a fine fibrovascular stalk (intraductal papillary neoplasia of liver [IPN-L]) resembling intraductal papillary mucinous neoplasm of pancreas is occasionally associated with hepatolithiasis. In this study, 136 cases of hepatolithiasis in Taiwan, between January 1998 and March 2000, and an additional 21 cases of IPN-L before December 1998, were examined histologically. IPN-L was found in 41 of 136 hepatolithiasis cases (30.1%). Sixty-two IPN-L cases (42 women and 20 men; age range, 59.8 +/- 10 years) were divided into 4 types (type 1, IPN-L with low-grade dysplasia, 23 cases; type 2, IPN-L with high grade dysplasia, 11 cases; type 3, IPN-L with in situ and microinvasive carcinoma, 13 cases; and type 4, IPN-L of types 2 and 3 with distinct invasive carcinoma, 15 cases). Intraductal spreading and glandular involvement were commonly observed in all types. About half of types 3 and 4 cases had mucobilia, and mucinous carcinoma was variably found in two thirds of group 4 patients. IPN-L frequently showed variable gastroenteric differentiation such as goblet cells and foveolar and colon-like metaplasia. IPN-L with goblet cells and colon-like metaplasia was frequently associated with overproduction of mucin and mucobilia (P <.01). In Japan, IPN-L was not frequent in hepatolithiasis (12 of 135 cases). In conclusion, IPN-L forms a spectrum of biliary neoplasm in hepatolithiasis. It often displays variable gastroenteric metaplasia and significant intraductal spread. IPN-L tends to progress to mucinous carcinoma. Formerly reported "mucin-producing intrahepatic cholangiocarcinoma" with a favorable prognosis is included in IPN-L.

Classification of thymic epithelial neoplasms: a controversial issue coming to an end?

The classification of thymic epithelial neoplasms has been one of the most controversial issues in tumor pathology. There are two opposing schools of pathologists holding different views regarding the classification of thymic epithelial neoplasms. One school of pathologists believe that histological classification of thymomas is not possible or useful. Another school of pathologists believe that thymomas can be histologically subclassified despite their complex histomorphology and that these histological subtypes correlate with their aggressiveness and clinical behavior. A compromised histological classification has been established by World Health Organization (WHO) to designate thymic epithelial neoplasms with letters and numbers. This classification should be adopted internationally to facilitate the communication among concerned pathologists and oncologists. A simple histological classification of thymomas based on cytomorphology and supported by cytokeratin expressions is proposed and compared to the WHO and Müller-Hermelink's histogenetic classifications.

Specificity of the histopathological triad for the diagnosis of toxoplasmic lymphadenitis: polymerase chain reaction study

Toxoplasmosis is a common cause of lymphadenopathy, but toxoplasmic cysts are not usually found in histological sections used for establishing diagnosis, except on extremely rare occasions. The histopathological triad of florid reactive follicular hyperplasia, clusters of epithelioid histiocytes, and focal sinusoidal distention by monocytoid B cells has been considered to be diagnostic of toxoplasmic lymphadenitis, but the validity of the histopathological triad is based indirectly on serological correlation only. The demonstration of Toxoplasma gondii DNA in lymph nodes displaying the histopathological triad will indicate the validity of the histopathological triad as the criterion for the histopathological diagnosis of toxoplasmic lymphadenitis. We used frozen tissues of 12 lymph nodes with the histopathological triad and tissues of 27 lymph nodes from patients with various other conditions (including 13 cases of follicular lymphoid hyperplasia, FLH; three cases of dermatopathic lymphadenopathy, DPL; two cases of plasmacytosis; two cases of Castleman's disease; two cases of metastatic adenocarcinoma; and five cases of lymphoma) to detect T. gondii DNA by polymerase chain reaction. Ten out of 12 lymph nodes with the triad and six out of 27 lymph nodes without the triad were positive for T. gondii DNA. Thus, the sensitivity of the triad was 62.5% (10/16) and the specificity was 91.3% (21/23). The predictive value of positive tests was 83.3% (10/12) and the predictive value of negative tests was 77.7% (21/27). The six cases positive for T. gondii DNA without the triad were four cases of FLH, one case of DPL, and one case of plasmacytosis. None of the neoplastic diseases was positive. The false positive and negative cases could be due to sampling problems or past T. gondii infection. The results confirm that the histopathological triad is highly specific for the diagnosis of toxoplasmic lymphadenitis and can be used confidently.

Induction of a mitosis delay and cell lysis by high-level secretion of mouse alpha-amylase from Saccharomyces cerevisiae

Some foreign proteins are produced in yeast in a cell cycle-dependent manner, but the cause of the cell cycle dependency is unknown. In this study, we found that Saccharomyces cerevisiae cells secreting high levels of mouse alpha-amylase have elongated buds and are delayed in cell cycle completion in mitosis. The delayed cell mitosis suggests that critical events during exit from mitosis might be disturbed. We found that the activities of PP2A (protein phosphatase 2A) and MPF (maturation-promoting factor) were reduced in alpha-amylase-oversecreting cells and that these cells showed a reduced level of assembly checkpoint protein Cdc55, compared to the accumulation in wild-type cells. MPF inactivation is due to inhibitory phosphorylation on Cdc28, as a cdc28 mutant which lacks an inhibitory phosphorylation site on Cdc28 prevents MPF inactivation and prevents the defective bud morphology induced by overproduction of alpha-amylase. Our data also suggest that high levels of alpha-amylase may downregulate PPH22, leading to cell lysis. In conclusion, overproduction of heterologous alpha-amylase in S. cerevisiae results in a negative regulation of PP2A, which causes mitotic delay and leads to cell lysis.

UV-induced increase in RNA polymerase activity in Xanthomonas oryzae pathovar oryzae

UV radiation is thought to inhibit transcriptional elongation, as a result of the formation of pyrimidine dimers in the DNA template, as well as to activate specific transcription factors. However, the effect of UV radiation on the enzymatic activity of RNA polymerase has remained unknown. With the use of an in vitro assay, UV irradiation of Xanthomonas oryzae pathovar oryzae has now been shown to increase RNA polymerase activity. This effect was maximal at a UV dose of approximately 12 J m(-2) and at approximately 60 min after irradiation. It was also not inhibited by pretreatment of cells with chloramphenicol, an inhibitor of protein synthesis. Immunoprecipitation with antibodies to the RNA polymerase core enzyme revealed that exposure of the bacterial cells to UV radiation induced the association of the core enzyme with a protein of approximately 29 kDa. These results demonstrate that UV radiation increases the activity of RNA polymerase, and they suggest that this effect may be related to the repair of DNA damage.

Granulomatous variant of chronic pigmented purpuric dermatosis: report of two cases

Two patients presenting with chronic pigmented purpuric dermatosis (CPPD) on the dorsum of both feet were found to show granulomatous inflammation superimposed on the pathological changes of CPPD. Two similar cases have been reported from Japan. The unique clinicopathological features of this group of patients suggest that they have a rare granulomatous variant of CPPD.

Structural and functional characterization of the lexA gene of Xanthomonas campestris pathovar citri

The role of the LexA protein and, specifically, its effect on recA expression were analyzed in Xanthomonas campestris pathovar citri (X.c. pv. citri). Overexpression of LexA from X.c. pv. citri, in the plant pathogen, as well as in Escherichia coli, results in increased sensitivity to the DNA-damaging agents mitomycin C and ultraviolet radiation, indicating that the recombinant X.c. pv. citri LexA protein is functional in a different bacterial species. Immunoblot analysis revealed that the overexpressed LexA protein functioned as a repressor of recA expression in X.c. pv. citri, and that the mitomycin C-induced increase in the abundance of RecA was accompanied by specific proteolysis of LexA that required RecA. Although the LexA protein from X.c. pv. citri also blocked the expression of recA in E. coli, the E. coli RecA protein was not able to support the autocatalytic cleavage of LexA from the plant pathogen. The transcription start site of the X.c. pv. citri lexA gene was identified, and the region upstream of this gene was shown to confer responsiveness to mitomycin C on a luciferase reporter gene construct. Electrophoretic mobility-shift assays demonstrated that X.c. pv. citri LexA interacts with the promoter region of X.c. pv. citri lexA, as well as with those of the recA genes of X.c. pv. citri and E. coli. These results indicate that LexA functions as a repressor of gene expression in X.c. pv. citri just as it does in E. coli.

Characterization of a Saccharomyces cerevisiae mutant with oversecretion phenotype

An oversecreting mutant of Saccharomyces cerevisiae was obtained from about 400 meiotic segregants derived from thediploid cells made by crossing the HBsAg-induced mutant NI-C with the wild-type strain Sey6211. When transformed with a plasmid containing mouse alpha-amylase cDNA, the mutant (NI-C-D4) exhibited an increased capacity (up to 13-fold) for the secretion of mouse alpha-amylase, higher than the parental strains and other standard wild-type strains. It was also shown that alpha-amylase secreted by the oversecreting mutant had a higher activity and contained more of the non-glycosylated form than the glycosylated form. This isolated oversecreting, low-glycosylation mutant may prove to be a potential S. cerevisiae host for the production of foreign proteins. Further genetic analysis suggested that the mutation responsible for the mutant's oversecretion was partially dominant and that both the oversecretion and low-glycosylation phenotypes were governed by a single chromosome mutation. These pleiotrophic phenotypes may be attributed to a defect in the synthesis of an ER-resident chaperone.

Presence of Epstein-Barr virus latent membrane protein 1 gene in the nasopharyngeal swabs from patients with nasopharyngeal carcinoma

BACKGROUND

Nasopharyngeal carcinoma (NPC) is the most common head and neck malignancy in southeastern China and Taiwan. Early detection of the local disease followed immediately by proper treatment is essential to increase the cure and survival rates. Because every NPC tumor cell carries Epstein-Barr Virus (EBV) genomes, detection of EBV genomic DNA such as latent membrane protein 1 gene (LMP1) might indicate the presence of NPC. We developed a simple and noninvasive technique of nasopharyngeal swabbing to acquire nasopharyngeal cells for detecting the presence of EBV genome. The aim of this study was to investigate the feasibility and reliability of this technique.

METHODS

We collected nasopharyngeal cells by means of a nasopharyngeal swabbing technique and detected the presence of EBV LMP1 with polymerase chain reaction (PCR). Thirty-eight swab specimens were obtained from patients with NPC who were newly diagnosed or were just beginning radiotherapy. Two groups of control subjects were recruited, including 20 patients with other head and neck cancers and eight family members of the NPC patients. An additional group of 65 NPC patients were enrolled in the course of regular follow-up after definitive radiotherapy.

RESULTS

All of the samples yielded sufficient DNA for PCR amplification. Thirty-six of 38 NPC swab samples were positive for EBV LMP1, and all the control subjects had swab sample results negative for EBV. All five patients with suspected local recurrence exhibited positive EBV test results.

CONCLUSIONS

Demonstration of EBV LMP1 in the nasopharyngeal swab specimens detected NPC with a sensitivity of 94.7% and specificity of 100%. This study confirms the reliability and feasibility of nasopharyngeal swab in the predicting and screening of NPC.

Reduction in mitochondrial respiratory capacity in Saccharomyces cerevisiae induced by expression of hepatitis B virus surface antigen

Transformants of Saccharomyces cerevisiae strain TL154 (MATalpha, trp1, leu2) expressing hepatitis B virus surface antigen showed reduced rates of cell growth compared with those of nontransformed cells. The rates of phosphorylative, nonphosphorylative, and uncoupled respiration in mitochondria isolated from the transformants were reduced relative to those of mitochondria derived from nontransformed cells, regardless of whether the cells were cultured in rich or minimal medium. The electrophoretic protein profiles of cell and mitochondrial extracts did not differ substantially between transformed and nontransformed cells. These results suggest that the reduced rate of mitochondrial respiration in the transformants may be due to impairment of metabolic function rather than to inhibition of the expression of components of the respiratory chain.

Pathologic studies of fatal cases in outbreak of hand, foot, and mouth disease, Taiwan

In 1998, an outbreak of enterovirus 71-associated hand, foot, and mouth disease occurred in Taiwan. Pathologic studies of two fatal cases with similar clinical features revealed two different causative agents, emphasizing the need for postmortem examinations and modern pathologic techniques in an outbreak investigation.

Acute encephalomyelitis during an outbreak of enterovirus type 71 infection in Taiwan: report of an autopsy case with pathologic, immunofluorescence, and molecular studies

We report a fatal case of enterovirus type 71 (EV 71) infection in an 8-year-old girl during a summer outbreak of hand, foot, and mouth disease in 1998 in Taiwan. The clinical course was rapidly progressive, with manifestations of hand, foot, and mouth disease, aseptic meningitis, encephalomyelitis, and pulmonary edema. The patient died 24 hours after admission. Postmortem study revealed extensive inflammation in the meninges and central nervous system and marked pulmonary edema with focal hemorrhage. Brain stem and spinal cord were most severely involved. The inflammatory infiltrates consisted largely of neutrophils involving primarily the gray matter with perivascular lymphocytic cuffing, and neuronophagia. The lungs and heart showed no evidence of inflammation. EV 71 was isolated from the fresh brain tissues and identified by immunofluorescence method with type-specific EV 71 monoclonal antibody. It was also confirmed by neutralization test and reverse-transcriptase polymerase chain reaction with sequence analysis. The present case was the first example in which EV 71 was demonstrated to be the causative agent of fatal encephalomyelitis during its epidemic in Taiwan.

Real-time PCR for quantitative detection of Toxoplasma gondii

The protozoan Toxoplasma gondii is one of the most common infectious pathogenic parasites and can cause severe medical complications in infants and immunocompromised individuals. We report here the development of a real-time PCR-based assay for the detection of T. gondii. Oligonucleotide primers and a fluorescence-labeled TaqMan probe were designed to amplify the T. gondii B1 gene. After 40 PCR cycles, the cycle threshold values (C(T)) indicative of the quantity of the target gene were determined. Typically, a C(T) of 25.09 was obtained with DNA from 500 tachyzoites of the T. gondii RH strain. The intra-assay coefficients of variation (CV) were 0.4, 0.16, 0.24, and 0.79% for the four sets of quadruplicate assays, with a mean interassay CV of 0.4%. These values indicate the reproducibility of this assay. Upon optimization of assay conditions, we were able to obtain a standard curve with a linear range (correlation coefficient = 0.9988) across at least 6 logs of DNA concentration. Hence, we were able to quantitatively detect as little as 0.05 T. gondii tachyzoite in an assay. When tested with 30 paraffin-embedded fetal tissue sections, 10 sections (33%) showed a C(T) of <40 and were scored as positive for this test. These results were consistent with those obtained through our nested-PCR control experiments. We have developed a rapid, sensitive, and quantitative real-time PCR for detection of T. gondii. The advantages of this technique for the diagnosis of toxoplasmosis in a clinical laboratory are discussed.