A PKU is a serum test, so it goes in a red top.
Blue
I can't remember the tube color (probably speckled or red for serum after clotting and centrifugation) but when I worked in a medical laboratory (until 2001) the key thing was to protect the specimen from light by wrapping the tube in aluminum foil!
If bacterium cannot use glucose the fermentation tube will stay the same color. Gas may also occur inside the fermentation tube.
To clean inside test-tubes properly. If it didn't exist it would have to be invented.
blue (citrate) tube
I would use the semi-colored tube.
The color tube u would use for the Creatinine test is GREEN...
SST
The color tube you use when drawing blood for a lab test depends on the type of test you are running. For a Na blood test you would use a red tiger strip tube.
blue top
the color tube is either gray or red..
A complete blood count (CBC) is drawn in a lavender-top tube.
serum,tiger tube
green
a lavender top tube
blue
Lavender