A shieldable collection needle assembly that shields the needle upon tube withdrawal includes a hub mounted on a needle cannula and a spring biased telescoping shield mounted on the hub. The needle assembly is matable with a needle holder adapted to receive the blood collection tubes. The needle assembly includes a retaining member moveably mounted on the hub and engageable with the telescoping shield when the collection tube is positioned in the needle holder. The retaining member prevents the telescoping shield from moving toward the fully extended position when engaged therewith. The telescoping shield will move toward the fully extended position when the retaining member is disengaged from the telescoping shield following removal of the collection tube from the needle holder.