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The utility of ADAMTS 13 in differentiating TTP from other acute thrombotic microangiopathies: results from the UK TTP Registry
Author(s) -
Hassan Sevda,
Westwood JohnPaul,
Ellis Debra,
Laing Chris,
Mc Guckin Siobhan,
Benjamin Sylvia,
Scully Marie
Publication year - 2015
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/bjh.13654
Subject(s) - medicine , adamts13 , intensive care medicine , thrombotic thrombocytopenic purpura , platelet
Summary Thrombotic microangiopathies ( TMA s) are frequently difficult to differentiate clinically, and measurement of ADAMTS 13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) remains vital in thrombotic thrombocytopenic purpura ( TTP ) diagnosis. We retrospectively reviewed cases referred for ADAMTS 13 testing, using UK TTP Registry screening data. Of a total 810 cases, 350 were confirmed as TTP . The 460 non‐ TTP cases comprised secondary TMA s (24·57%) and haemolytic uraemic syndrome ( HUS ) (27·17% aHUS , 2·83% Shiga‐like toxin‐producing E. coli [ STEC ]‐ HUS ); the remainder were TMA s with no clear association, not TMA s, or had no confirmed diagnosis. ADAMTS 13 levels were significantly lower in TTP than STEC ‐ HUS , aHUS and other TMA s. TTP patients had significantly lower platelet count (15 × 10 9 /l; range 0–96) than aHUS (57 × 10 9 /l; range 13–145, P < 0·0001) or STEC ‐ HUS (35 × 10 9 /l; range 14–106, P < 0·0001); they also had lower creatinine levels (92 μmol/l; range 43–374) than aHUS (255 μmol/l; range 23–941, P < 0·0001) and STEC ‐ HUS (324 μmol/l; range 117–639, P < 0·0001). However, 12/34 (35·3%) aHUS patients had a platelet count <30 × 10 9 /l and 26/150 (17·3%) of TTP patients had a platelet count >30 × 10 9 /l; 23/150 (15·3%) of TTP patients had a creatinine level >150 μmol/l. This study highlights the wide variety of TMA presentations, and confirms the utility of ADAMTS 13 testing in TTP diagnosis.