ChemoMetec SCC-400 - Manual (Page 21)

2!Cell!counting!with!the!NucleoCounter!SCC0400!
7!
The!instrument!is!configured!in!such!a!manner!that!the!entire!volume!of!the!
sample/reagent!mixture!is!drawn!from!the!sample!container.!Upon!activation!a!volume!for!
the!rinsing!of!previous!sample!is!drawn!into!the!internal!flow!system!and!thereupon!the!
sample!compartment!is!flushed!with!a!portion!of!the!sample/reagent!mixture!in!order!to!
allow!the!recording!of!fluorescent!images!representing!the!sample!being!analyzed.!Upon!
completion!of!analysis!the!remainder!of!the!sample/reagent!mixture!as!well!as!some!air!is!
drawn!into!the!flow!system.!The!air!removes!significant!part!of!the!sample!making!the!
rinsing!with!the!following!sample!more!efficient.!!
Upon!completion!of!analysis!or!if!the!instrument!is!to!be!idle!for!more!than!just!few!
minutes!it!is!recommended!to!rinse!the!sample!compartment.!!
2.2.2 Sample-Compartment-Cleaning-
The!image!analysis!method!of!the!NucleoView!SCC0400!offers!considerable!stability,!when!
eliminating!non0cellular!objects!from!the!image,!and!thus!producing!valid!results!even!
under!extreme!conditions.!On!the!other!hand,!the!quality!of!the!cell!count!is!best!assured!
by!keeping!the!sample!compartment!as!clean!as!possible.!
Contamination!on!the!exterior!of!the!sample!compartment!is!typically!gathered!on!the!
surfaces!of!the!sample!compartment!when!it!is!outside!of!the!instrument.!Therefore!good!
care!should!be!given!to!protect!the!surfaces!outside!the!instrument,!and!if!the!sample!
compartment!is!to!be!removed!from!the!instrument!for!a!considerable!time!it!should!be!
stored!in!a!dust0free!container!such!as!a!plastic!bag.!!
The!surfaces!of!the!sample!compartment!are!best!cleaned!by!using!dry!pressurized!air,!and!
in!severe!cases!by!gently!wiping!them!clean!with!a!dry!non0scratching!dust!free!cloth.!!
Contamination!on!the!inside!of!the!sample!compartment!is!typically!either!one!or!more!
somatic!cells!that!adhere!to!the!inner!wall!of!the!sample!compartment!or!a!foreign!object,!
such!as!hair,!which!is!wedged!between!the!walls!of!the!sample!compartment.!Adhering!
somatic!cells!constitute!a!potential!problem,!mainly!in!the!analysis!of!samples!with!low!
somatic!cell!count!as!if!no!measure!are!taken!against!it,!then!they!are!present!in!each!
image.!!
To!prevent!this,!samples!below!about!550,000!in!SCC!are!measured!by!analyzing!the!result!
of!subtracting!two!images!from!each!other.!This!subtraction!removes!any!feature!in!the!
image!which!appears!on!the!same!spot!in!the!two!images,!e.g.!stationary!cells.!Other!
objects,!such!as!pieces!of!hair,!which!are!stationary,!will!also!be!removed!from!image!
analysis!in!this!manner,!but!to!the!extent!these!objects!are!not!stationary!the!image!
analysis!does!not!take!them!into!consideration!when!counting!somatic!cells!due!to!the!
obvious!difference!in!the!appearance!of!cells!and!the!much!larger!objects.!
Contamination!on!the!inside!of!the!sample!compartment!are!removed!by!performing!a!
cleaning!operation!of!the!instrument,!during!which!a!cleaning!solution!is!flushed!through!
the!flow!system!including!the!sample!compartment.!
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