Michigan Risk Score = sum of points for five risk factors present at the time of PICC placement.

Predictor	Definition	Points
Another central venous catheter	Present when the PICC is placed	+1
WBC >12.0 x 10⁹/L	At or near PICC placement	+1
PICC lumens	1, 2, or 3-4 lumens	0, +1, or +2
History of DVT/VTE	Never, >30 days prior, or within 30 days	0, +2, or +3
Active cancer	On chemotherapy or admitted for a cancer-related problem	+3

Total score	Risk class	Estimated PICC-DVT probability
0	Class I	0.9%
1-2	Class II	1.6%
3-4	Class III	2.7%
5 or more	Class IV	4.7%

Michigan Risk Score for PICC-Related Thrombosis