Improved Performance of the Automated Slide Preparation Unit, Sysmex SP-100

• Improved Performance of the Automated Slide Preparation Unit, Sysmex SP-100

AUTHOR(S)

Jan Willem Bron^＊１, Gerard Jellema^＊２, Richard Noordervliet^＊１, Fred Reymer^＊１,
Henk A. Baelde^＊１, Judy Paauwe^＊１, Gerard J.den Ottolander^＊１, and
Hanneke C. Kluin-Nelemans^＊１

*1 Central Clinical Hematology Laboratory, Department of Hematology, Leiden University     Medical Center
*2 Goffin Meyvis

SUMMARY

Morphologic evaluation of blood films remains the cornerstone for most hematologic malignancies. In our hands, the quality of slides generated by the newly installed Sysmex automated slide preparation unit SP-100 was less than that of manually prepared and stained slides using the default settings on installation. Artifacts in white blood cell morphology, and an increase of damaged cells hampered correct interpretation. Moreover, morphology on the second slide from the duplicate slide option was consistently poorer than the first. To improve on this, a series of studies was performed. It appeared that adaptation of the angle and speed of the spreader glass adjusted for the hematocrit ( Hct ) very much improved the quality of the cells. The most important improvement, however, was caused by a prolongation of the pre-fix time period to 60 seconds. The default settings for smear angles (°) related to the Hct ( <25, 25-35, 35-45, 45-55 and >55 ) were changed to smaller cohorts ( <30, 30-35, 35-40, 40-45 and >45 ) according to the prevalence of Hct levels in our laboratory, thus enabling easier adaptations at smaller Hct variations. In contrast, variations in the temperature of the May-Grünwald stain, variations in fixation by replacing May-Grünwald for Methanol, variations in the type of slides used or prolongation of the storage time of blood samples ( up to 3 hours ) did not have any influence on the quality of the blood films.

When CLL patients were tested-known for the high percentage of smudge cells-it appeared, however, that the percentage of smudge cells was always much higher in the SP-100 generated smears than in the manually prepared smears.

Following these adaptations, the option ‘duplicate smears’ was re-tested and compared with singlely prepared slides. No differences were then found between the differentials and the quality of cellular morphology.

In conclusion, systematically performed adaptations using patients’ material can largely improve the quality of SP-100 generated blood films.

KEY WORDS

WBC Differential, SP-100, Automated Slide Preparation Unit