Criteria of Ruutu et al for Hematopoietic Stem Cell Transplant-Associated Microangiopathy

 

Features distinguishing this from TTP and HUS:

(1) absence of systemic microthrombi

(2) absence of a severe deficiency in ADAMTS13

(3) a different spectrum of clinical symptoms

(4) poor response to plasmapheresis

 

Criteria:

(1) schistocytes

(2) de novo, prolonged or progressive thrombocytopenia

(3) increase in LDH

(4) decrease in hemoglobin concentration (anemia) and/or increased need for blood transfusion

(5) serum haptoglobin concentration (which decreases as it binds free hemoglobin)

Parameter	Finding	Points
schistocytes	<= 4%	0
	> 4%	1
platelet count	< 50,000 per µL	1
	> 50% decrease from baseline	1
	neither	0
serum LDH	normal	0
	gradual or transient increase	0
	sudden and persistent increase	1
hemoglobin or blood transfusion	decrease in hemoglobin	1
	increase in blood transfusion needs	1
	neither	0
serum haptoglobin	normal or increased	0
	decreased	1

 

total score =

= SUM(points for all 5 criteria)

 

Interpretation:

• minimum score: 0

• maximum score: 5

• The diagnosis of HSCT-associated microangiopathy is made when the score is 5.

 

Performance:

• The paper says that both the sensitivity and specificity of the diagnostic criteria are 100%.

• These findings seem somewhat miraculous since there are cutoffs and diseases that overlap. The criteria do not even include a requirement that there not be another condition that can explain the findings better.