Total haemoglobin is one of the most frequently ordered laboratory tests, both in the hospital and ambulatory. Haemoglobin concentration provides information about the status of anaemia in the population and guides many clinical diagnoses and therapeutic interventions. Portuguese External Quality Evaluation Program (PNAEQ) provides 4 survey per year with 2 samples each since it is important for medical laboratories to know about the stability and performance of their methods over the time.
The main objective of this study was to apply a linear regression model for long-term evaluation of the performance of laboratories in haemoglobin quantification by comparing the laboratory individual results with the consensus mean of each round, after outliers exclusion. To evaluate the performance of the laboratory, the long-term analytical CV (LCVa) and the total analytical bias were established.N/

Brito, Cristina

Cardoso, Ana

Clemente, Vera

Correia, Helena

Faria, Ana Paula

Meijer, Piet

Miranda, Armandina

Silva, Susana Pereira

Repositório Científico do Instituto Nacional de Saúde

Table 3: “Desirable” performance goals and quality specifications for Haemoglobin. [CVt – Total biologic variation; Cvi – Within subject variation; CVb – Between suject variation] and percentage of laboratories in the study within the desirable performance goals EQA total haemoglobine quantification – Long-term analytical performance for thirty Portuguese Laboratories Total haemoglobin is one of the most frequently ordered laboratory tests, both in the hospital and ambulatory. Haemoglobin concentration provides information about the status of anaemia in the population and guides many clinical diagnoses and therapeutic interventions. Portuguese External Quality Evaluation Program (PNAEQ) provides 4 survey per year with 2 samples each since it is important for medical laboratories to know about the stability and performance of their methods over the time. The main objective of this study was to apply a linear regression model for long-term evaluation of the performance of laboratories in haemoglobin quantification by comparing the laboratory individual results with the consensus mean of each round, after outliers exclusion. To evaluate the performance of the laboratory, the long-term analytical CV (LCVa) and the total analytical bias were established. Armandina Miranda1, Helena Correia1, Ana Cardoso1, Cristina Brito1, Vera Clemente1, Susana Silva1, Piet Meijer2, Ana Faria1+ 1 Instituto Nacional de Saúde Doutor Ricardo Jorge, Departamento de Epidemiologia, Unidade de Avaliação Externa da Qualidade;  2 ECAT Foundation;  +Correspondência operacional do programa PNAEQ – pnaeq@insa.min-saude.pt  Discussion and Conclusion Table 1: Consensus values, interlaboratory CV and number of outliers for the 12 surveys/samples used in the study  Referênces 1 - Piet Meijer et all; Long-Term Analytical Performance of Hemostasis Field Methods as Assessed by Evaluation of the Results of an External Quality Assessment Program for Antithrombin; Clinical Chemistry 48:7 1011–1015 (2002).  2 - Desirable Biological Variation Database specifications available in https://www.westgard.com/biodatabase1.htm 3 - Fraser CG et al. Proposals for setting generally applicable quality goals solely based on biology. Ann Clin Biochem 1997; 34: 8 – 12.    Aim Methods Results A linear regression model was applied to quantitative haemoglobin results to evaluate  the long-term analytical performance of thirty of the participating laboratories in the PNAEQ external quality assessment programme (2014-2016), using the results of twelve blood EDTA samples with different hemoglobin concentrations1, from 6 surveys (2 samples each). Participants were randomly selected concerning laboratories from hospital (10) and ambulatory (20). To assess the long-term performance in this model the long-term analytical CV (LCVa) and total analytical Bias were used. Two laboratories were excluded from the analysis (1 outlier and 1 user of point-of-care equipment). We evaluate also the number of laboratories that fulfill the widely accepted analytical performance goals based on the biological variation.2,3  All statistical analyses were performed with Microsoft Excel namely with “Long-term calculation file” provided by Piet Meijer. EQALM Symposium 2016 13-14 October 2016 Barcelona- Spain The consensus values used on the analysis are presented on Table 1. The median of LCVa was 1,4% (range 0,4%-3,1%) and of  Total Bias 1,1% (range 0,1%-3,3%) (Table 2).  According to the specification goals we found that the LCVa was less than 0,58 times the total biological variation (diagnostic testing) for all laboratories (100%) and was less than 0,5 times the within biological variation (monitoring testing) in 62 % of the laboratories.83% of the laboratories had a total bias less than 0,25 of the total biological variation (Table 3). The frequency distribuition of the laboratories LCVa and Total Bias are represented on graphics 1 and 2.   Graph 1: Histogram of the individual  LCVa values (%) for haemoglobin for the 28 laboratories included in the study   “Desirable” Performance goals  Hb, g/L Quality specifications  Hb, g/L Laboratories within the desirable performance goals, % Imprecision (Diagnostic) % < 0,58 CVt ( √(CVi2   + CVb2)) 4,3 100 Imprecision (Monitoring ) % < 0,5 CVi 1,4 62 Total Bias% 0,25 √(CVi2   + CVb2) 1,8 83 Survey/ Sample No. of participants Consensus value, g/L CV, %  No. of outliers 4114 65 65,2 2,47 8 4214 65 136,9 1,78 7 1115 72 137,7 1,45 9 1215 72 93,3 1,66 10 2115 70 151,5 3,05 3 2215 70 170,4 5,58 3 3115 75 106,8 2,20 4 3215 75 150,3 2,02 4 4115 76 135,5 2,14 3 4215 76 135,4 2,19 4 1116 66 128,0 1,51 5 1216 66 135,0 1,23 5 1 10 7 6 3 0 1 0 2 4 6 8 10 12 0,5 1 1,5 2 2,5 3 >3 No. of laboratories LCVa, % 3 11 6 4 2 1 1 0 2 4 6 8 10 12 0,5 1 1,5 2 2,5 3 >3 No. of  laboratories  Total Bias, %  As reflected by the results the overall performance remained satisfactory. All laboratories evaluated accomplished the quality specifications for  imprecision (diagnostic) and 83% for Total Bias. However only 62% met the quality specification as imprecision (monitoring).  It is important to make aware for the standardization of analytical procedures, namely calibrations of equipments, and continuous monitoring of laboratory good practices.   Participation in External Quality Assessment schemes is of extreme importance, as it provides information to the laboratory about its own method performance both in a single survey as well as over time and allows the evaluation of the needs for improvements.  It’s highly recommendable the internal investigation of significantly discordant results aiming the continuous improvement of quality diagnostic services.       LCVa, % Bias,  % n 28 28 Mean  1,4 1,3 Median 1,4 1,1 Range 0,4-3,1 0,1-3,3 Table 2: Discriptive analysis of Long-term analytical CV and total Bias results  Graph 2: Histogram of the individual Total Bias values (%) for haemoglobin for the 28 laboratories included in the study 

EQA total haemoglobine quantification: long-term analytical performance for thirty Portuguese Laboratories

É importante para os laboratórios clínicos avaliarem o desempenho dos seus
métodos ao longo do tempo. O principal objetivo deste estudo foi a aplicação
de um modelo de regressão linear para avaliação a longo prazo, do desempenho
dos laboratórios na quantificação da hemoglobina, comparando os resultados
individuais do laboratório com a média de consenso de cada ensaio,
após a exclusão de outliers. Para avaliar o desempenho do laboratório foram
calculados o coeficiente de variação analítico a longo prazo (LCVa) e o Bias
total analítico. O modelo de regressão linear foi aplicado aos resultados quantitativos
da hemoglobina para avaliar o desempenho analítico a longo prazo de
trinta laboratórios que participam no programa de avaliação externa da qualidade
PNAEQ (2014-2016), utilizando os resultados de doze amostras controlo
de sangue em EDTA, com diferentes concentrações de hemoglobina. Os
participantes foram selecionados aleatoriamente, sendo incluídos laboratórios
hospitalares e ambulatórios. As variáveis introduzidas para avaliar o desempenho
a longo prazo neste modelo foram o CV analítico a longo prazo (LCVa) e o
Bias total analítico. Dois laboratórios foram excluídos da análise. Foi determinado
o número de laboratórios que cumpriram os objetivos de desempenho
analítico definido com base na variação biológica. A mediana do LCVa foi de
1,4% (variação de 0,4% -3,4%). O LCVa foi 0,58 vezes inferior à variação biológica
total (teste de diagnóstico) para todos os laboratórios (100%) e foi 0,5
vezes inferior à variação biológica intraindividual (teste de monitorização) em
62% dos laboratórios. A mediana do Bias total foi de 1,1% (variação de 0,1%
-3,3%), sendo que 83% dos laboratórios apresentaram um Bias total inferior
a 0,25 da variação biológica total. A participação em programas de avaliação
externa da qualidade é de extrema importância, uma vez que fornece informações
ao laboratório sobre o desempenho do seu método tanto numa única
análise, bem como ao longo do tempo e permite a avaliação da necessidade
de melhoria.It is impor tant for medical laboratories to know about the stability and performance
of their methods over the time. The main objective of this study
was to apply a linear regression model for long-term evaluation of the performance
of laboratories in haemoglobin quantification by comparing the
laborator y individual results with the consensus mean of each round, af ter
outliers exclusion. To evaluate the per formance of the laborator y, the long
term analytical CV (LCVa) and the total analytical bias were established. A
linear regression model was applied to quantitative haemoglobin results
to evaluate the long-term analytical per formance of thir ty laboratories that
par ticipate in the PNAEQ external quality assessment programme (2014-
2016), using the results of twelve blood EDTA samples with dif ferent hemoglobin
concentrations. Par ticipants were randomly selected concerning
laboratories from hospital and ambulator y. The variables introduced to define
the long-term per formance in this model were the long-term analytical
CV (LCVa) and total analytical Bias. Two laboratories were excluded from
the analysis (one outlier and one that uses point-of-care equipment). We
evaluate also the number of laboratories that fulfill the widely accepted analytical
per formance goals based on the biological variation. The median
LCVa was 1.4% (range 0.4%-3.4%). The LCVa was less than 0.58 times the
total biological variation (diagnostic testing) for all laboratories (100%) and
was less than 0.5 times the within biological variation (monitoring testing)
in 62 % of the laboratories. The median Total Bias was 1.1% (range 0.1%-
3.3%). 83% of the laboratories had a total bias less than 0.25 of the total biological
variation. Par ticipation in External Quality Assessment schemes is
of extreme impor tance, as it provides information to the laborator y about
its own method per formance both in a single sur vey as well as over time
and allows the evaluation of the needs for improvements

Silva, Susana

Faria, Ana

EQA total haemoglobine quantification: long-term analytical performance for thirty Portuguese laboratories

Scientific Repository of the National Health Institute Doutor Ricardo Jorge

http://repositorio.insa.pt/bitstream/10400.18/4109/1/Boletim_Epidemiologico_Observacoes_N17_2016_artigo7.pdf

EQA total haemoglobine quantification: long-term analytical performance for thirty Portuguese Laboratories

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Repositório Científico do Instituto Nacional de Saúde

Repositório Científico do Instituto Nacional de Saúde

Scientific Repository of the National Health Institute Doutor Ricardo Jorge