Reliability of a rapid hematology stain for sputum
                  cytology

This was a cross-sectional study comparing the standard technique (May-Grünwald-Giemsa stain) with a rapid hematology stain (Diff-Quik). Of the 50 subjects included in the study, 21 had asthma, 19 had COPD, and 10 were healthy (controls). From the induced sputum samples collected, we prepared four slides: two were stained with May-Grünwald-Giemsa, and two were stained with Diff-Quik. The slides were read independently by two trained researchers blinded to the identification of the slides. The reliability for cell counting using the two techniques was evaluated by determining the intraclass correlation coefficients (ICCs) for intraobserver and interobserver agreement. Agreement in the identification of neutrophilic and eosinophilic sputum between the observers and between the stains was evaluated with kappa statistics.

Results:

In our comparison of the two staining techniques, the ICCs indicated almost perfect interobserver agreement for neutrophil, eosinophil, and macrophage counts (ICC: 0.98-1.00), as well as substantial agreement for lymphocyte counts (ICC: 0.76-0.83). Intraobserver agreement was almost perfect for neutrophil, eosinophil, and macrophage counts (ICC: 0.96-0.99), whereas it was moderate to substantial for lymphocyte counts (ICC = 0.65 and 0.75 for the two observers, respectively). Interobserver agreement for the identification of eosinophilic and neutrophilic sputum using the two techniques ranged from substantial to almost perfect (kappa range: 0.91-1.00).

Conclusions:

The use of Diff-Quik can be considered a reliable alternative for the processing of sputum samples.

Sputum; Sputum; Azure stains

Characteristic	Groups			p
	Asthma	COPD	Control
	(n = 21)	(n = 19)	(n = 10)
Age, years^b	47.3 (22-68)	62.8 (52-77)	38.4 (21-58)	< 0.001. and 0.2
Female gender^c	12 (57.0)	5 (26.3)	7 (70.0)	0.03
Pre-BD FEV1,% of predicted	55.3 ± 11.9	50.2 ± 18.2	102.2 ± 7.8	0.1* and < 0.001.*
Post-BD FEV1,% of predicted	64.9 ± 11.7	52.7 ± 18.2	104.5 ± 8.7	0.02* and < 0.001.*
Pre-BD FEV1/FVC, %	58.3 ± 9.5	52.5± 13.8	80.4 ± 5.0	0.4* and < 0.001.*
Post-BD FEV1/FVC,%	61.3 ± 9.2	53.2 ± 14.4	82.4 ± 4.6	0.06* and < 0.001.*
Pre-BD ΔFEV1, L	0.29 ± 0.29	0.07 ± 0.09	0.08 ± 0.08	0.003, 0.02, and 1.0**
Post-BD ΔFEV1, %	19.1 ± 17.6	6.1 ± 7.4	2.5 ± 2.4	0.005, 0.002, and 1.0**

Interobserver agreement	Sputum type	kappa	p
Diff-Quik stain	Eosinophilic	1.000	< 0.001
Diff-Quik stain	Neutrophilic	1.000	< 0.001
May-Grünwald-Giemsa stain	Eosinophilic	0.905	< 0.001
May-Grünwald-Giemsa stain	Neutrophilic	0.960	< 0.001
Intraobserver agreement	Sputum type	kappa	p
Observer 1	Eosinophilic	0.746	< 0.001
Observer 1	Neutrophilic	0.801	< 0.001
Observer 2	Eosinophilic	0.758	< 0.001
Observer 2	Neutrophilic	0.760	< 0.001

Sociedade Brasileira de Pneumologia e Tisiologia SCS Quadra 1, Bl. K salas 203/204, 70398-900 - Brasília - DF - Brasil, Fone/Fax: 0800 61 6218 ramal 211, (55 61)3245-1030/6218 ramal 211 - São Paulo - SP - Brazil
E-mail: jbp@sbpt.org.br

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[1] Correspondence to: Jéssica Gonçalves Universidade Federal de Santa Catarina, Hospital Universitário Núcleo de Pesquisa em Asma e Inflamação das Vias Aéreas Campus Universitário, Trindade, CEP 88040-970, Florianópolis, SC, Brasil Tel. 55 48 3721-8134. E-mail: jessicagoncalvesufsc@gmail.com

Brasil

Brasil

Reliability of a rapid hematology stain for sputum cytology* * Study carried out at the Federal University of Santa Catarina University Hospital, Florianópolis, Brazil.

Objective:

Methods:

Results:

Conclusions:

Reliability of a rapid hematology stain for sputum cytology^* * Study carried out at the Federal University of Santa Catarina University Hospital, Florianópolis, Brazil.