A new spectrophotometric method to detect residual amounts of peroxide after reprocessing hemodialysis filters

Oliveira, Moacir de; Dalboni, Maria Aparecida; Iizuka, Ilson Jorge; Manfredi, Silvia Regina; Guimarães, Nadia Karina; Andreoli, Maria Claudia Cruz; Matos, Ana Cristina Carvalho; Batista, Marcelo Costa; Santos, Bento Fortunato Cardoso; Cendoroglo Neto, Miguel

doi:10.1590/S1679-45082011GS1945

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Health Economics and Management • Einstein (São Paulo) 9 (1) • Jan-Mar 2011 • https://doi.org/10.1590/S1679-45082011GS1945 copy

A new spectrophotometric method to detect residual amounts of peroxide after reprocessing hemodialysis filters

Authorship SCIMAGO INSTITUTIONS RANKINGS

ABSTRACT

Objective:

Reuse of hemodialysis filters is a standard practice and the sterilizing chemical most often employed is peracetic acid. Before starting the dialysis session, filters and lines are checked for residual levels of peracetic acid by means of a non-quantitative colorimetric test that is visually interpreted. The objective of this study was to investigate a new quantitative spectrophotometric test for detection of peracetic acid residues.

Methods:

Peracetic acid solutions were prepared in concentrations ranging from 0.01 to 10 ppm. A reagent (potassium-titanium oxide + sulfuric acid) was added to each sample in proportions varying from 0.08 to 2.00 drops/mL of solution. Optical densities were determined in a spectrophotometer using a 405-nm filter and subjected to visual qualitative test by different observers.

Results:

A relation between peroxide concentrations and respective optical densities was observed and it was linear with R² > 0.90 for all reagent/substrate proportions. The peak optical densities were obtained with the reagent/substrate ratio of 0.33 drops/mL, which was later standardized for all further experiments. Both qualitative and quantitative tests yielded a specificity of 100%. The quantitative test was more sensitive than the qualitative test and resulted in higher positive and negative predictive values. There was a difference between observers in the qualitative test and some samples with significant amounts of peroxide were not detected.

Conclusion:

A quantitative spectrophotometric test may improve detection of residues of peracetic acid when compared to the standard visual qualitative test. This innovation may contribute to the development of safer standards for reuse of hemodialysis filters.

Keywords:
Renal dialysis/instrumentation; Renal dialysis/methods; Peracetic acid; Spectrophotometry/methods; Peroxides

Reagent (drops)	Substrate (mL)	Proportion R/S (drops/mL)	0.01-1 ppm		0.01-5 ppm		0.01-10 ppm
Reagent (drops)	Substrate (mL)	Proportion R/S (drops/mL)	R²	p - value	R²	p - value	R²	p-value
1	12	0.08	0.96	0.004	0.32	0.19	0.64	0.02
1	9	0.11	0.99	< 0.00001	0.93	0.002	0.76	0.008
1	6	0.17	0.99	0.0001	0.99	0.0003	0.85	0.003
3	12	0.25	0.99	< 0.00001	0.99	< 0.000001	0.90	0.0007
1	3	0.33	0.99	0.0002	0.97	< 0.000001	0.92	0.0004
3	6	0.5	0.99	0.00004	0.99	< 0.000001	0.99	< 0.00001
3	3	1	0.98	0.0003	0.99	< 0.000001	0.99	< 0.00001
6	3	2	0.92	0.004	0.99	0.000004	0.98	< 0.00001

Reagent (drops)	Substrate (mL)	Proportion R/S (drops/mL)	Optical densities
Reagent (drops)	Substrate (mL)	Proportion R/S (drops/mL)	0.01 ppm	0.1 ppm	0.5 ppm	1 ppm	5 ppm	10 ppm
1	12	0.08	0	0.002	0.014	0.020	0.017	0.029
1	9	0.11	0	0.004	0.021	0.043	0.094	0.091
1	6	0.17	0.001	0.003	0.020	0.045	0.120	0.126
3	12	0.25	0	0.004	0.023	0.045	0.195	0.228
1	3	0.33	0.003	0.008	0.022	0.045	0.204	0.254
3	6	0.5	0	0.003	0.022	0.048	0.230	0.430
3	3	1	0	0.002	0.019	0.044	0.238	0.532
6	3	2	0	0	0.009	0.032	0.204	0.539

		PPV (%)	NPV (%)	Sensitivity (%)	Specifcity (%)
Laboratory personnel (n = 6)
	0.01 ppm	5	47	5	100
	0.1 ppm	0	100	0	100
	0.5 ppm	78	22	78	100
	1 ppm	100	0	100	100
Dialysis staff (n = 12)
	0.01 ppm	5	47	5	100
	0.1 ppm	11	88	11	100
	0.5 ppm	44	56	44	100
	1 ppm	100	0	100	100
Quantitative test
	0.01 ppm	88	12	88	100
	0.1 ppm	100	100	100	100
	0.5 ppm	100	100	100	100
	1 ppm	100	100	100	100

Concentration (ppm)	Laboratory personnel (%)	Dialysis staff (%)	p-value
0.01	5	5	1
0.5	78	44	0.01
1	100	100	1

Instituto Israelita de Ensino e Pesquisa Albert Einstein Avenida Albert Einstein, 627/701 , 05651-901 São Paulo - SP, Tel.: (55 11) 2151 0904 - São Paulo - SP - Brazil
E-mail: revista@einstein.br

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[1] Corresponding author: Moacir Oliveira – Avenida Albert Einstein, 627 – Morumbi – CEP 05651-901 – São Paulo (SP), Brazil - Tel.: 11 2151-1233 - e-mail: moacir@einstein.br