Clinical Prediction Score - Thrombotic Thrombocytopenic Purpura (TTP)

Description

Bentley et al developed a simple score for predicting the probability of a patient having thrombotic thrombocytopenic purpura (TTP). The findings were correlated with the patient's ADAMTS13 activity. The authors are from the University of Utah and ARUP Laboratories in Salt Lake City.

Parameters:

(1) serum creatinine in mg/dL

(2) platelet count per µL

(3) plasma D-dimer in µg/mL (mg/L)

(4) reticulocyte count in percent

(5) indirect serum bilirubin in mg/dL

Parameter	Finding	Points
serum creatinine	<= 2.0 mg/dL	0
	> 2.0 mg/dL	-11.5
platelet count	<= 35,000 per µL	0
	> 35,000 per µL	-30
plasma D-dimer	<= 4.0 µg/mL	0
	> 4.0 mg/dL	-10
reticulocyte count	<= 3%	0
	> 3%	21
serum indirect bilirubin	<= 1.5 mg/dL	0
	> 1.5 mg/dL	20.5

where:

• It may take some time to generate a suitable reticulocyte response.

• The method used to assay plasma D-dimer and its normal reference range were not stated.

total score =

= SUM(points for all 5 parameters)

Interpretation:

• minimum score: -51.5

• maximum score: 41.5

• The higher the score the more likely that the patient has TTP.

Total Score	Probability of TTP
<= 19.5	0%
20 to 30	40%
>= 30.5	100%

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Description

Specialty

Objective

ICD-10

Clinical Prediction Score of Bentley et al for Thrombotic Thrombocytopenia Purpura (TTP)

Purpose: To evaluate a patient for thrombotic thrombocytopenic purpura (TTP) using the predictive score of Bentley et al.

Description

Specialty

Objective

ICD-10