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  1. Fulltext Diagnosis of Dengue Infection Using Conventional and Biosensor Based Techniques
    Parkash O, Shueb RH
    Viruses, 2015 Oct 19;7(10):5410-27.
    PMID: 26492265 DOI: 10.3390/v7102877
    Dengue is an arthropod-borne viral disease caused by four antigenically different serotypes of dengue virus. This disease is considered as a major public health concern around the world. Currently, there is no licensed vaccine or antiviral drug available for the prevention and treatment of dengue disease. Moreover, clinical features of dengue are indistinguishable from other infectious diseases such as malaria, chikungunya, rickettsia and leptospira. Therefore, prompt and accurate laboratory diagnostic test is urgently required for disease confirmation and patient triage. The traditional diagnostic techniques for the dengue virus are viral detection in cell culture, serological testing, and RNA amplification using reverse transcriptase PCR. This paper discusses the conventional laboratory methods used for the diagnosis of dengue during the acute and convalescent phase and highlights the advantages and limitations of these routine laboratory tests. Subsequently, the biosensor based assays developed using various transducers for the detection of dengue are also reviewed.
    Matched MeSH terms: Clinical Laboratory Techniques/methods*
  2. Fulltext Stacking gels: A method for maximising output for pulsed-field gel electrophoresis
    Heng SK, Heng CK, Puthucheary SD
    Indian J Med Microbiol, 2009 Apr-Jun;27(2):142-5.
    PMID: 19384038 DOI: 10.4103/0255-0857.49428
    Pulsed field gel electrophoresis (PFGE), the gold standard of molecular typing methods, has a major disadvantage of an unusually long electrophoretic time. From the original protocol of 6 days, it was modified to 3 days and subsequently to a single day. We describe the procedure of stacking five to six gels one on top of another in order to increase and maximize the output in a shorter time without compromising the resolution and reproducibility. All the variables that affect pulsed field gels during electrophoresis were taken into consideration. We firstly optimized the parameters to be used and secondly determined whether stacking of five to six gels had any effect on the molecular separation during electrophoresis in comparison with a single gel run. DNA preparation, restriction, electrophoresis, staining and gel documentation was carried out based on previously published methods. Gels were analysed using BioNumerics and dice coefficient and unweighted pair group methods were used to generate dendrograms based on 1.5% tolerance values. Identical band profiles and band resolution-separation were seen in the PFGE patterns with single gel and multiple stacking gels. Cluster analysis further strengthened the fact that results from stacking gels were reproducible and comparable with a single gel run. This method of stacking gels saves time and maximizes the output at the same time. The run time for a single gel was about 28 hours, but with six stacked gels the run time was 54 hours compared with 28 x 6 = 168 hours if they were run separately as single gels thus saving time of 67.86%. Beside the big factor of saving time, stacking gels save resources (electricity, reagents, water, chemicals and working time) by increasing the sample throughput in a shorter time without compromising on quality of data. But optimization of working parameters is vital depending on the PFGE system used.
    Matched MeSH terms: Clinical Laboratory Techniques/methods*
  3. Fulltext Diagnostic techniques for COVID-19 and new developments
    Sheikhzadeh E, Eissa S, Ismail A, Zourob M
    Talanta, 2020 Dec 01;220:121392.
    PMID: 32928412 DOI: 10.1016/j.talanta.2020.121392
    COVID-19 pandemic is a serious global health issue today due to the rapid human to human transmission of SARS-CoV-2, a new type of coronavirus that causes fatal pneumonia. SARS -CoV-2 has a faster rate of transmission than other coronaviruses such as SARS and MERS and until now there are no approved specific drugs or vaccines for treatment. Thus, early diagnosis is crucial to prevent the extensive spread of the disease. The reverse transcription-polymerase chain reaction (RT-PCR) is the most routinely used method until now to detect SARS-CoV-2 infections. However, several other faster and accurate assays are being developed for the diagnosis of COVID-19 aiming to control the spread of infection through the identification of patients and immediate isolation. In this review, we will discuss the various detection methods of the SARS-CoV-2 virus including the recent developments in immunological assays, amplification techniques as well as biosensors.
    Matched MeSH terms: Clinical Laboratory Techniques/methods*
  4. Fulltext Public health and clinical importance of amoebiasis in Malaysia: a review
    Tengku SA, Norhayati M
    Trop Biomed, 2011 Aug;28(2):194-222.
    PMID: 22041740 MyJurnal
    Entamoeba histolytica, the causative agent of human amoebiasis remains a significant cause of morbidity and mortality in developing countries and is responsible for up to 100,000 deaths worldwide each year. Entamoeba dispar, morphologically indistinguishable from E. histolytica is more common in humans in many parts of the world. Similarly Entamoeba moshkovskii, which was long considered to be a free-living amoeba is also morphologically identical to E. histolytica and E. dispar, and is highly prevalent in some E. histolytica endemic countries. Humans are the host of infection and there would not appear to be other meaningful animal reservoirs of E. histolytica. Entamoeba. histolytica can be present in sewage and contaminated water. The infection is mainly transmitted via ingestion of water or food contaminated by faeces containing E. histolytica cysts. Clinical features of amoebiasis range from asymptomatic colonization to amoebic dysentery and invasive extraintestinal amoebiasis, which is manifested most commonly in the form of abscesses in liver and lungs. The epidemiology of amoebiasis has dramatically changed since the separation of E. histolytica and E. dispar species and the worldwide prevalence of these species has not been estimated until recently. Morever, E. moshkovskii, another morphologically indistinguishable human parasitic Entamoeba was not mentioned or considered as a contributor to the prevalence figures in endemic areas. Amoebiasis is still a major health problem especially in aboriginal settlements and amongst people living in remote area in Malaysia. However, until now there is only one data currently available to indicate the true prevalence and incidence of E. histolytica and E. dispar. Further studies are needed to determine the burden of E. histolytica, E. dispar and E. moshkovskii infections in Malaysia. In the present review, we briefly summarize all methods use in diagnosing Entamoeba species, ranging from microscopic identification to molecular detection such as culture and isoenzyme analysis, antibody detection tests, antigen detection tests, immunochromatographic assays, conventional PCR, real-time PCR and loop-mediated isothermal amplification (LAMP).
    Matched MeSH terms: Clinical Laboratory Techniques/methods
  5. Sunway Medical Laboratory Quality Control Plans Based on Six Sigma, Risk Management and Uncertainty
    Jairaman J, Sakiman Z, Li LS
    Clin. Lab. Med., 2017 Mar;37(1):163-176.
    PMID: 28153364 DOI: 10.1016/j.cll.2016.09.013
    Sunway Medical Centre (SunMed) implemented Six Sigma, measurement uncertainty, and risk management after the CLSI EP23 Individualized Quality Control Plan approach. Despite the differences in all three approaches, each implementation was beneficial to the laboratory, and none was in conflict with another approach. A synthesis of these approaches, built on a solid foundation of quality control planning, can help build a strong quality management system for the entire laboratory.
    Matched MeSH terms: Clinical Laboratory Techniques/methods
  6. Fulltext COVID-19 screening test by using random oropharyngeal saliva
    Rao M, Rashid FA, Sabri FSAH, Jamil NN, Seradja V, Abdullah NA, et al.
    J Med Virol, 2021 Apr;93(4):2461-2466.
    PMID: 33393672 DOI: 10.1002/jmv.26773
    An optimal clinical specimen for accurate detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by minimizing the usage of consumables and reduce hazard exposure to healthcare workers is an urgent priority. The diagnostic performance of SARS-CoV-2 detection between healthcare worker-collected nasopharyngeal and oropharyngeal (NP + OP) swabs and patient performed self-collected random saliva was assessed. Paired NP + OP swabs and random saliva were collected and processed within 48 h of specimen collection from two cohort studies which recruited 562 asymptomatic adult candidates. Real-time reverse-transcription polymerase chain reaction targeting Open reading frame 1a (ORF1a) and nucleocapsid (N) genes was performed and the results were compared. Overall, 65 of 562 (28.1%) candidates tested positive for COVID-19 based on random saliva, NP + OP swabs, or both testing techniques. The detection rate of SARS-CoV-2 was higher in random saliva compared to NP + OP testing (92.3%; 60/65 vs. 73.8%; 48/65; p 
    Matched MeSH terms: Clinical Laboratory Techniques/methods
  7. Cloning, expression, and purification of the hemolysin/cytolysin (HlyE antigen) from Salmonella enterica serovar Typhi: potential application for immunoassay development
    Ong EB, Anthony AA, Ismail A, Ismail A, Lim TS
    Diagn Microbiol Infect Dis, 2013 Sep;77(1):87-9.
    PMID: 23790417 DOI: 10.1016/j.diagmicrobio.2013.05.010
    The hemolysin (HlyE) protein of Salmonella enterica serovar Typhi was reported to be antigenic. This work describes the cloning, expression, and purification of a hexahistidine-tagged HlyE protein under native conditions. Immunoblot analysis and a competitive enzyme-linked immunosorbent assay using sera from typhoid patients showed the presence of HlyE-specific antibodies in circulation.
    Matched MeSH terms: Clinical Laboratory Techniques/methods*
  8. Fulltext Review of cases with the emerging fifth human malaria parasite, Plasmodium knowlesi
    Kantele A, Jokiranta TS
    Clin Infect Dis, 2011 Jun;52(11):1356-62.
    PMID: 21596677 DOI: 10.1093/cid/cir180
    Human malaria has been known to be caused by 4 Plasmodium species, with Plasmodium falciparum causing the most-severe disease. Recently, numerous reports have described human malaria caused by a fifth Plasmodium species, Plasmodium knowlesi, which usually infects macaque monkeys. Hundreds of human cases have been reported from Malaysia, several cases have been reported in other Southeast Asian countries, and a few cases have been reported in travelers visiting these areas. Similarly to P. falciparum, P. knowlesi can cause severe and even fatal cases of disease that are more severe than those caused by the other Plasmodium species. Polymerase chain reaction is of value for diagnosis because P. knowlesi infection is easily misdiagnosed as less dangerous Plasmodium malariae infection with conventional microscopy. P. knowlesi infection should be suspected in patients who are infected with malaria in Southeast Asia. If human-mosquito-human transmission were to occur, the disease could spread to new areas where the mosquito vectors live, such as the popular tourist areas in western India.
    Matched MeSH terms: Clinical Laboratory Techniques/methods
  9. Fulltext Evaluation of dot immunogold filtration assay (DIGFA) for rapid serodiagnosis of eosinophilic meningitis due to Angio-strongylus cantonensis (Nematoda: Metastrongyloidea)
    Eamsobhana P, Prasartvit A, Gan XX, Yong HS
    Trop Biomed, 2015 Mar;32(1):121-5.
    PMID: 25801261
    Angiostrongylus cantonensis is the most frequent cause of eosinophilic meningitis in humans in Thailand and worldwide. Because of difficulty of recovering the Angiostrongylus larvae from infected patients, detection of parasite-specific antibodies is used to support clinical diagnosis. This study tested serum samples from eosinophilic meningitis patients and individuals at risk of infection with A. cantonensis to evaluate a recently developed simple and rapid dot-immunogold filtration assay (DIGFA) for detection of specific antibodies against A. cantonensis. Purified 31-kDa glycoprotein of A. cantonensis and protein A colloidal gold conjugate were employed to detect the 31-kDa anti-A. cantonensis antibody in patients sera from the parasite endemic areas of northeast Thailand. The results were compared with those obtained by dot-blot enzyme-linked immunosorbent assay (ELISA) with 31-kDa A. cantonensis antigen. The overall positivity rate of DIGFA and dot-blot ELISA for A. cantonensis infection in 98 clinically diagnosed cases from three highly endemic districts in Khon Kaen province were 39.79% and 37.75%, respectively. Among 86 sera of subjects at risk of infection with A. cantonensis, 24.41% were positive by DIGFA and 23.25% by dot-blot ELISA. There were good correlation between the visual grading of DIGFA and dot-blot ELISA in both groups of defined sera. DIGFA is as sensitive and specific as dot-blot ELISA for confirming eosinophilic meningitis due to A. cantonensis infection, with advantages of simplicity, rapidity and without the use of specific and expensive equipment, and can be used in field settings.
    Matched MeSH terms: Clinical Laboratory Techniques/methods*
  10. Fulltext Efficacies of two in-house indirect ELISAs for diagnosis of amoebic liver abscess
    Tan ZN, Wong WK, Noordin R, Zeehaida M, Olivos GA, Lim BH
    Trop Biomed, 2013 Jun;30(2):250-6.
    PMID: 23959490 MyJurnal
    Entamoeba histolytica causes amoebic diarrhoea, colitis and liver abscess (ALA). Diagnosis of ALA is difficult, as most patients do not have simultaneous intestinal amoebic infection. At Hospital Universiti Sains Malaysia (HUSM), diagnosis of ALA relies on a combination of clinical findings, ultrasound examination of the liver and serodiagnosis using a commercial kit. In this study, two in-house indirect ELISAs were developed and evaluated. One of the in-house assays utilises E. histolytica crude soluble antigen (CSA) to detect serum IgG specific to the parasite whereas the other uses E. histolytica ether extract antigen (EEA). Preparation of CSA requires a sonicator to lyse the amoeba whereas EEA was prepared by chemically solubilizing the trophozoites. Based on the cut-off value of mean optical density + 3SD, CSA-ELISA showed 100% (24/24) sensitivity and 93.33% (210/225) specificity; while EEA-ELISA showed 91.67% (22/24) sensitivity and 95.11% (214/225) specificity. In conclusion, both the in-house indirect ELISAs were found to be efficacious for diagnosis of ALA; and the EEA is easier to prepare than the commonly used CSA.
    Matched MeSH terms: Clinical Laboratory Techniques/methods*
  11. Fulltext Early experience with universal preoperative and pre-procedural screening for COVID-19 in low-risk pediatric surgical patients requiring general anesthesia
    Sii CKS, Lee JA, Nah SA
    Pediatr Surg Int, 2020 Dec;36(12):1407-1411.
    PMID: 33068142 DOI: 10.1007/s00383-020-04760-7
    PURPOSE: The COVID-19 pandemic has placed extraordinary demands on healthcare services worldwide. Some have reported increased viral transmission to healthcare workers during aerosol-generating procedures such as intubation. We report our experience with universal preoperative and preprocedural screening for COVID-19 in children requiring general anaesthesia with low risk of having the infection.

    METHODS: This was a data review involving children aged 

    Matched MeSH terms: Clinical Laboratory Techniques/methods*
  12. Fulltext Cloning, expression, and immunocharacterization of surface protein containing an altered thrombospondin repeat domain (SPATR) from Plasmodium knowlesi
    Palaeya V, Lau YL, Mahmud R, Chen Y, Fong MY
    Malar J, 2013;12:182.
    PMID: 23734702 DOI: 10.1186/1475-2875-12-182
    Plasmodium knowlesi is the fifth species identified to cause malaria in humans and is often misdiagnosed as Plasmodium malariae due to morphological similarities. The development of an inexpensive, serological detection method utilizing antibodies specific to P. knowlesi would be a valuable tool for diagnosis. However, the identification of specific antigens for these parasites remains a major challenge for generating such assays. In this study, surface protein containing an altered thrombospondin repeat domain (SPATR) was selected as a potentially specific antigen from P. knowlesi. Its multistage expression by sporozoites, asexual erythrocytic forms and gametocytes, along with its possible role in liver cell invasion, suggests that SPATR could be used as a biomarker for diagnosis of P. knowlesi.
    Matched MeSH terms: Clinical Laboratory Techniques/methods*
  13. Fulltext The diagnostic sensitivity of dengue rapid test assays is significantly enhanced by using a combined antigen and antibody testing approach
    Fry SR, Meyer M, Semple MG, Simmons CP, Sekaran SD, Huang JX, et al.
    PLoS Negl Trop Dis, 2011 Jun;5(6):e1199.
    PMID: 21713023 DOI: 10.1371/journal.pntd.0001199
    BACKGROUND: Serological tests for IgM and IgG are routinely used in clinical laboratories for the rapid diagnosis of dengue and can differentiate between primary and secondary infections. Dengue virus non-structural protein 1 (NS1) has been identified as an early marker for acute dengue, and is typically present between days 1-9 post-onset of illness but following seroconversion it can be difficult to detect in serum.
    AIMS: To evaluate the performance of a newly developed Panbio® Dengue Early Rapid test for NS1 and determine if it can improve diagnostic sensitivity when used in combination with a commercial IgM/IgG rapid test.
    METHODOLOGY: The clinical performance of the Dengue Early Rapid was evaluated in a retrospective study in Vietnam with 198 acute laboratory-confirmed positive and 100 negative samples. The performance of the Dengue Early Rapid in combination with the IgM/IgG Rapid test was also evaluated in Malaysia with 263 laboratory-confirmed positive and 30 negative samples.
    KEY RESULTS: In Vietnam the sensitivity and specificity of the test was 69.2% (95% CI: 62.8% to 75.6%) and 96% (95% CI: 92.2% to 99.8) respectively. In Malaysia the performance was similar with 68.9% sensitivity (95% CI: 61.8% to 76.1%) and 96.7% specificity (95% CI: 82.8% to 99.9%) compared to RT-PCR. Importantly, when the Dengue Early Rapid test was used in combination with the IgM/IgG test the sensitivity increased to 93.0%. When the two tests were compared at each day post-onset of illness there was clear differentiation between the antigen and antibody markers.
    CONCLUSIONS: This study highlights that using dengue NS1 antigen detection in combination with anti-glycoprotein E IgM and IgG serology can significantly increase the sensitivity of acute dengue diagnosis and extends the possible window of detection to include very early acute samples and enhances the clinical utility of rapid immunochromatographic testing for dengue.
    Matched MeSH terms: Clinical Laboratory Techniques/methods*
  14. Indicators of prolonged hospital stay in hyperemesis gravidarum
    Tan PC, Jacob R, Quek KF, Omar SZ
    Int J Gynaecol Obstet, 2006 Jun;93(3):246-7.
    PMID: 16682037
    Matched MeSH terms: Clinical Laboratory Techniques/methods*
  15. Fulltext Comparison between Quantitative Buffy Coat (QBC) and Giemsa-stained Thin Film (GTF) technique for blood protozoan infections in wild rats
    Sahimin N, Alias SN, Woh PY, Edah MA, Mohd Zain SN
    Trop Biomed, 2014 Sep;31(3):422-31.
    PMID: 25382468 MyJurnal
    The quantitative buffy coat (QBC) technique and conventional Giemsa thin blood smear was compared to determine the sensitivity and specificity of the technique in detecting blood parasitic infection of the rodent populations from four urban cities in Peninsular Malaysia. A total of 432 blood samples from four rat species (Rattus norvegicus, Rattus rattus diardii, Rattus exulans and Rattus argentiventer) were screened using both techniques and successfully detected two blood protozoan species (Trypanosoma lewisi and Plasmodium sp.) with Trypanosoma lewisi predominantly infecting the population. Results showed that Giemsa-stained thin film (GTF) was the better detection method on blood parasitemia (46.7%) compared to Quantitative Buffy Coat method (38.9%) with overall detection technique sensitivity and specificity at 83.2% and 74.8% respectively. The sensitivity in detection of Trypanosoma lewisi was 84.4% with value slightly lower for Plasmodium sp. infections at 76.6%. Statistical analysis proved that GTF technique was significantly more sensitive in the detection of blood protozoan infections in the rodent population compared to QBC (p<0.05).
    Matched MeSH terms: Clinical Laboratory Techniques/methods*
  16. Fulltext Active infection and morphometric study of Trypanosoma evansi among horses in Peninsula Malaysia
    Elshafie EI, Sani RA, Hassan L, Sharma R, Bashir A, Abubakar IA
    Trop Biomed, 2013 Sep;30(3):444-50.
    PMID: 24189674 MyJurnal
    Apart from occasional reports of clinical disease affecting horses, there is no information about Trypanosoma evansi in horses in Peninsula Malaysia. Thus, a cross-sectional study was conducted in eight states in Peninsula Malaysia to determine the active presence of T. evansi in horses. A total of 527 blood samples were obtained and examined by haematocrit centrifugation technique (HCT), Giemsa-stained thin blood smear (GSS), morphometric measurements, polymerase chain reaction (PCR) and cloning of PCR products. The results showed an overall parasitological prevalence of 0.57% (3/527, CI: 1.6-0.19%) with both HCT and GSS. Morphometric study revealed the mean total length of the trypanosomes including the free flagellum was 27.94 ± 2.63 μm. PCR successfully amplified a trypanosome specific 257 bp in 1.14% of samples (6/527, CI: 2.4-0.52%) and was confirmed by nucleotide sequences. The mean packed cell volume (PCV) for the positive cases detected by HCT was lower (23% ± 7.00) compared to the positive cases detected by PCR alone in the state of Terengganu (35% ± 4.73). In conclusion, this study showed T. evansi infection occurred in low frequency in horses in Peninsula Malaysia, and anaemia coincided with parasitaemic animals. PCR is considered as a sensitive diagnostic tool when parasitaemia is undetectable. The slight lengthier mean of parasite and anaemia may indicate a virulent strain of T. evansi circulating throughout the country. Thus, it's highly recommended to shed light on host-parasite relationship for better epidemiological understanding.
    Matched MeSH terms: Clinical Laboratory Techniques/methods
  17. Fulltext Seroprevalence of toxocariasis among Orang Asli (Indigenous people) in Malaysia using two immunoassays
    Romano N, Nor Azah MO, Rahmah N, Lim Y AL, Rohela M
    Trop Biomed, 2010 Dec;27(3):585-94.
    PMID: 21399601 MyJurnal
    Toxocariasis is a zoonotic helminthic infection of humans caused by the dog roundworm (Toxocara canis) or cat roundworm (Toxocara cati). There are two main human syndromes: visceral larva migrans (VLM), which are characterized by symptoms associated with major organs and ocular larva migrans (OLM), in which pathological effects on the host are restricted to the eye and the optic nerve. The present study evaluated the seroprevalence of toxocariasis among the Orang Asli with an IgG4-ELISA using recombinant antigens (rTES-26, rTES-30 and rTES-120) and an IgG-ELISA commercial kit (Cypress Diagnostic, Belgium). A total of 188 serum samples were analyzed using IgG4-ELISA recombinant antigens while 83 were tested using IgG-ELISA. Overall, 9 out of 188 (4.8%) samples were positive with the former assay: rTES-26 (2.7%) and rTES-30 (2.1%); and 63 out of 83 (75.9%) were positive with the IgG-ELISA. In general, the seroprevalence of toxocariasis among males (9.5%) was higher compared to females (1%). Children below 12 years (6.3%) have higher seroprevalence rate compared to adults (1.2%). Out of 59 IgG positive samples, 56 (94.9%) were also positive with soil-transmitted helminth (STH) infections which may indicate high false positivity. None of the IgG4- ELISA positive samples were positive with STH infections. Of 9 positive samples with IgG4-ELISA, 7 were also positive with IgG-ELISA giving the probability of true cases. The present finding indicated that exposure to Toxocara infection is not unusual among Malaysian aborigines, and it affects both sexes and all age groups. As a prevention strategy, more effective public health programmes to promote better understanding on the consequences of toxocariasis among the Orang Asli communities are deemed necessary.
    Matched MeSH terms: Clinical Laboratory Techniques/methods
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