A multi-rule Shewhart chart for quality control in clinical chemistry.

Westgard, James O.; Barry, Patricia L.; Hunt, Marian R.; Groth, Torgny

doi:10.1093/clinchem/27.3.493

Cited by 715 publications

(266 citation statements)

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“…Westgard multirule quality control rules 1 3s , 2 2s , and 4 1s were applied to control results to detect random and systematic errors (Westgard et al, 1981).…”

Section: Quality Assurance Of the Methodsmentioning

confidence: 99%

Mean platelet size related to glycoprotein‐specific autoantibodies and platelet‐associated IgG

Javela¹,

Kekomäki²

2007

Int J Lab Hematology

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Recent evidence suggests that platelet-associated glycoprotein-specific (GP) antibodies represent true positive autoantibodies and can therefore be taken as the gold standard. Earlier tests, which aimed at detecting platelet-associated IgG (PA-IgG), might have been hampered, e.g. by the variation of platelet size in thrombocytopenic patients. In this study, 206 samples with increased PA-IgG from consecutive thrombocytopenic patients were tested further for GP-specific antibodies with a monoclonal antibody immobilized platelet antigen test (MAIPA) using a combination of a GP IIbIIIa-specific and a GP IbIX-specific antibody for immobilization or, in a separate assay, GP V-specific antibody. Mean platelet size was recorded as forward scatter (FSC) of platelets in flow cytometric analysis of PA-IgG. GP-specific antibodies were detected in 49 (24%) of the 206 patient samples. Their presence correlated well with increased PA-IgG ( R = 0.769). The mean platelet size and mean fluorescence intensity (MFI) of PA-IgG were both significantly increased in patients compared with healthy controls ( n = 112; P < 0.0001). Notably, PA-IgG was associated with platelet size within the platelet population of both healthy controls and patients ( R = 0.999). Further, the probability of GP IIbIIIa and/or IbIX and GP V-specific PA-IgG tended to increase with the mean platelet size of the patients ( P = 0.045). In conclusion, large platelets bound more IgG than platelets of normal size, which may explain at least in part the reported low specificity of total PA-IgG measurement. As the PA-IgG displays low specificity compared with the gold standard, its use as such may be abandoned and replaced by tests for platelet-associated GP-specific autoantibodies.

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“…Westgard multirule quality control rules 1 3s , 2 2s , and 4 1s were applied to control results to detect random and systematic errors (Westgard et al, 1981).…”

Section: Quality Assurance Of the Methodsmentioning

confidence: 99%

Mean platelet size related to glycoprotein‐specific autoantibodies and platelet‐associated IgG

Javela¹,

Kekomäki²

2007

Int J Lab Hematology

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“…For this exercise, the action limit was set at a single violation of the 3 standard deviation rule. General indications for possible problems were set at two out of three results exceeding the same warning limit, nine consecutive readings on the same side of the mean, or six consecutive readings showing a continuous rising or decreasing trend (Westgard et al 1981).…”

Section: Interpretation Of Resultsmentioning

confidence: 99%

“…An attempt has been made to apply the principle of Westgard Rules used for clinical chemistry (Westgard et al 1981) to microbiological control charts. The principles that work so well in clinical chemistry and serological assays (Gray 1994) may not all hold true for microbiology.…”

Section: Discussionmentioning

confidence: 99%

The use of LenticulesTM for the process control of enumeration techniques in food and environmental microbiology

Lightfoot¹,

Richardson²,

Harford³

2001

J Appl Microbiol

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Aims: Lenticules TM consist of control-dried plano convex discs in which biologically-active materials are contained within a water-soluble matrix. They can be produced to contain stable numbers of bacteria from 10 cfu lenticule ±1 to 10 8 cfu lenticule ±1 with a wide variety of organisms. These experiments were carried out to validate their use as a tool for internal quality control in quantitative microbiology. Methods and Results: The Lenticules TM were used routinely in standard quantitative microbiological procedures across ®ve laboratories. Results showed the materials to be stable, homogenous and capable of identifying systematic errors. Conclusions: The Lenticules TM provide suitable, stable control materials. Signi®cance and Impact of the Study: Routine internal quality control of quantitative measurements is greatly improved; the materials are easy to use and enable comparisons between laboratories to be made.

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“…The OD of individual control runs are plotted in the chart and compared with the standard deviation. When it exceeds the average ±2 SDs, this is considered as a warning for bad quality of the run, which can be rejected if additional criteria apply (Westgard et al 1981).…”

Section: Standardization Of Elisa Readingsmentioning

confidence: 99%

Detection of trypanosome‐specific antibodies in saliva, towards non‐invasive serological diagnosis of sleeping sickness

Lejon

Jamonneau

Solano

et al. 2006

Tropical Med Int Health

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Summaryobjective The detection of trypanosome-specific antibodies in saliva is technically feasible, and, if clinically validated, could become an attractive option for non-invasive diagnosis of sleeping sickness. We wanted to optimize the test format of an enzyme-linked immunosorbent assay (ELISA)-based antibody detection system.methods Different ELISA formats for antibody detection in serum and saliva were developed and standardized. Saliva and serum samples were collected from 78 patient and 128 endemic control samples, and sensitivity and specificity of saliva ELISAs, serum ELISAs and the card agglutination test for trypanosomiasis (CATT), were evaluated.results All ELISA formats showed sensitivity and specificity above 90%. Saliva ELISAs showed a similar test performance as serum ELISAs and the CATT on whole blood or serum.conclusions This study confirms the potential of trypanosome-specific antibody detection in saliva.

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A multi-rule Shewhart chart for quality control in clinical chemistry.

Cited by 715 publications

References 0 publications

Mean platelet size related to glycoprotein‐specific autoantibodies and platelet‐associated IgG

Mean platelet size related to glycoprotein‐specific autoantibodies and platelet‐associated IgG

The use of LenticulesTM for the process control of enumeration techniques in food and environmental microbiology

Detection of trypanosome‐specific antibodies in saliva, towards non‐invasive serological diagnosis of sleeping sickness

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