Bendapudi et al developed the Plasmic score as an aid in the diagnosis of thrombotic thrombocytopenic purpura (TTP). The authors are from Massachusetts General Hospital, Beth Israel Deaconess Medical Center, University of Alabama and Brigham and Women's Hospital.
Basis of Plasmic: platelet, lysis, active cancer, stem cell or solid organ transplant, MCV, INR, creatinine.
Outcome: ADAMTS13 deficiency (< 10%)
Parameters:
(1) platelet count per microliter
(2) MCV in femtoliters (fL)
(3) serum creatinine in mg/dL
(4) INR
(5) evidence of hemolysis (reticulocyte count > 2.5%, indirect serum bilirubin > 2.0 mg/dL, absence of haptoglobin)
(6) history of active cancer
(7) history of bone marrow or solid organ transplantation
|
Parameter |
Finding |
Points |
|
platelet count |
>= 30,000 per µL |
0 |
|
|
< 30,000 per µL |
1 |
|
MCV |
>= 90 fL |
0 |
|
|
< 90 fL |
1 |
|
serum creatinine |
< 2 mg/dL |
1 |
|
|
>= 2 mg/dL |
0 |
|
INR |
< 1.5 |
1 |
|
|
>= 1.5 |
0 |
|
evidence of hemolysis |
no |
0 |
|
|
yes |
1 |
|
history of active cancer |
no |
1 |
|
|
yes |
0 |
|
history of transplant |
no |
1 |
|
|
yes |
0 |
total score =
= SUM(points for all 7 parameters)
Interpretation:
• minimum score: 0
• maximum score: 7
• The higher the score the greater the risk for severe ADAMTS13 deficiency.
|
Total Score |
Risk of ADAMTS Deficiency |
|
0 to 4 |
low |
|
5 or 6 |
intermediate |
|
7 |
high |
Limitations:
• Pre-existing elevation of INR or serum creatinine may cause the Pramic score to be lower than expected in a patient with TTP.
Specialty: Hematology Oncology, Clinical Laboratory
