Fibrinogen, Ddimer and Factor XIII testing Data from UK NEQAS (Blood Coagulation) Disclosure. Factor XIII. UK NEQAS data

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1 Fibrioge, Ddimer ad Factor XIII testig Data from UK NEQAS (Blood Coagulatio) Steve Kitche UK NEQAS (Blood Coagulatio & Sheffield Haemophilia ad Thrombosis Cetre) Disclosure Relevat Fiacial Relatioship(s) NONE Off Label Usage NONE Factor XIII Deficiecy leads to characterisitic bleedig history May text books report that to (U/dl) factor XIII is sufficiet for haemostasis Simple clot solubility test sesitive to - factor XIII i plasma What level of FXIII causes bleedig? Jackobse & Godal Losowsky & Miloszewski Seitz et al Level required for haemostasis Half of patiets with 5 - levels bled UK NEQAS data Samples i trisodium citrate ( CPD iappropriate) Lyophilised Screeig tests i labs Assays i - cetres FXIII Clot lysis screeig tests Clot with thrombi ( u/ml) or calcium or a mix Challege clot with 5M urea or acetic acid (Jeigs et al JTH : ; -8)

2 Treated patiet with Factor XIII deficiecy : Trough level of u/dl (UK NEQAS = labs) Iterpretatios by clottig aget Treated patiet with Factor XIII deficiecy : Trough level of u/dl Iterpretatios by clottig aget Borderlie Abormal 5 Borderlie Abormal Calcium Calcium Thrombi Treated patiet with Factor XIII deficiecy : Trough level of u/dl Iterpretatios by clottig aget Treated patiet with Factor XIII deficiecy : Trough level of u/dl Iterpretatios by lysig aget Borderlie Abormal Borderlie Abormal Calcium Thrombi Ca + Thrombi Urea Treated patiet with Factor XIII deficiecy : Trough level of u/dl Iterpretatios by lysig aget 8 Relatioship betwee FXIII solubility tests ad FXIII levels 7 5 Borderlie Abormal Sample XIII deficiet (=7) XIII ihibitor (=) XIII post treatmet (=) FXIII level (u/dl) Ca + Urea Ca + A Acid Thrombi + Urea Thrombi + A Acid < /- - + Urea Acetic acid + : positive screeig test

3 Clot solubility Mixtures of FXIII deficiet ad ormal plasma FXIII assays FXIII deficiecy weeks post treatmet Media. u/dl (), rage -55u/dl (May ) Ca + Urea Ca + A Acid T + Urea T + A Acid FXIII FXIII FXIII FXIII Others Berichrom + : positive screeig test 5 5 > FXIII u/dl FXIII assays : plasma Media. u/dl () (May ) Coclusios Factor XIII assay results variable 8 8 FXIII u/dl Others Berichrom I screeig tests Thrombi to clot ad acetic acid to lyse is most sesitive Calcium to clot ad urea to lyse is isesitive to levels above 5u/dl UK NEQAS : Methods i use Factor XIII screeig exercise, May 997 UK NEQAS : Methods i use Factor XIII screeig exercise, May Calcium + Urea Calcium + A Acid Calcium + Urea/A Acid Calcium/Thrombi + Urea Calcium/Thrombi + A Acid Calcium/Thrombi + Urea/A Acid Thrombi + Urea Thrombi + A Acid Thrombi + Urea/A Acid Calcium + Urea Calcium + A Acid Calcium + Urea/A Acid Calcium/Thrombi + Urea Calcium/Thrombi + A Acid Calcium/Thrombi + Urea/A Acid Thrombi + Urea Thrombi + A Acid Thrombi + Urea/A Acid PT reaget + Urea/A Acid

4 UK NEQAS : Methods i use Factor XIII screeig exercise, May Calcium + Urea Calcium + A Acid Calcium + Urea/A Acid Calcium/Thrombi + Urea DDimer testig UK NEQAS results Calcium/Thrombi + A Acid Calcium/Thrombi + Urea/A Acid Thrombi + Urea Thrombi + A Acid Thrombi + Urea/A Acid PT reaget + Urea/A Acid Samples for DDimer Pool of plasmas from + hospital patiets with elevatio i DDimer (Itesive care, post op etc).5m buffered trisodium citrate DDimer results o pooled patiet plasma S7 N media Auto DD 5 Auto FEU 5 Slide/latex 5 Lyophilised ad despatched by post, ad tested with local system Rage CV () results 5 Results S5 (5) (methods with > ) D - dimer by the same Automated assay Assay Dade-Behrig DD+ Triity Biotech/biopool IL Stago VIDAS N 85 5 Media g/ml Rage CV Uits DD DD DD DD FEU FEU FEU D-dimer ( g/ml)

5 What cut-offs are used? (S7) uits media Rage DD -5 7 Dade-Behrig/CA series DD -7 Dade-Behrig/BC series DD 9-5 IL/ACL series DD IL/Futura series DD 55-5 FEU 5-5 Biomerieux VIDAS FEU Stago FEU 5 - Triity Biopool IL Wide rage of cut-offs for same method Biomerieux VIDAS Stago uits media Rage Rage 5 DD DD DD FEU FEU FEU Do cetres miss the elevated levels associated with VTE? Cetres who reported DVT excluded Media DDimer 5 g/ml (FEU) or 5 (ddimer uits) S7 9/9 (9.8 ) reported DVT excluded 7 used semi quatitative tile based latex methods At least used a clearly iappropriate cut-off - a mixture of outlyig test result ad possibly iappropriate cut-offs Some cetres use iappropriate cutoffs for VTE ad/or ormal rages techique Cut off for DVT from cliical studies < <<<<5<<7<8<9< <5 D-dimer ( g/ml) Results i cetres usig < 5, 5 8 Method Media 5 Do cetres report raised values whe DDimer is below VTE cutoff? 5

6 Results S (methods with >/= ) DVT exclusio S participats told Low pretest probability Assay Dade-Behrig DD+ Biopool Auto IL Stago (FEU) (FEU) VIDAS (FEU) N Media g/ml Media cutoff VTE Media upper ormal Assay Dade-Behrig DD+ Biopool Auto IL Stago (FEU) (FEU) VIDAS (FEU) DVT Excluded DVT ot excluded ot excluded 8 5 Prospects for Stadardisatio Variability betwee methods ca be reduced from 75 to 5 by calibratio agaist method specific calibrats ( Miejer et al ) Use of a commo calibrat removes most of the iter assay variability ( Dempfle ) Fibrioge testig UK NEQAS data CV improves - fold if results calibrated agaist commo plasmas Improvemet is comig!! FIBRINOGEN RESULTS UK NEQAS Clauss or PT derived assay? 8 Medias Clauss.5 g/l PT der. g/l. g/l.8 g/l. g/l. g/l. g/l. g/l.8 g/l. g/l. g/l. g/l. g/l.8 g/l. g/l. g/l. g/l 5. g/l

7 Derivatio of Fibrioge from chage i light scatter durig Prothrombi time measuremet - PT Derived Fibrioge LIGHT SCATTER Thromboplasti/Ca added TIME Icreased light scatter by 5 uits : Fibrioge =. g/l 5 uits : Fibrioge =. g/l INACCURACY OF PT DERIVED FIBRINOGENS ACL/PT Fib HS/ IL calibrat ACL/Fib C/IL calibrat Subjects PT der.9 g/l Clauss. g/l (ACL). g/l (KC) OAC PT der 5.7 g/l Clauss.58 g/l (ACL).7 g/l (KC ) (Chitolie et al 99) PT DERIVED DURING THROMBOLYTIC THERAPY ACL/Thromborel S/pooled plasma S&G/Bovie IIa/pooled plasma samples with Clauss <.g/l - PT derived.8 -. g/l 5 samples with Clauss.-. g/l - PT derived. -.8 g/l Hoffma & Verhappe 988 Fibrioge (g/l) PT derived Fibrioge (Iovi ad HS plus o ACL ad Sysmex) - Calibratio with differet plasmas sample Clauss clear a b c d e f Mackie, Lawrie, Kitche et al Clarity of referece plasma affects discrepacy betwee Clauss ad PT derived Fibrioges (Two differet test plasmas) Differece betwee PT derived ad Clauss (g/l) Plasma Opacity (A5) /8 dil) Fibrioge assays Calibratio Clauss Referece plasma calibrated agaist st or d WHO Iteratioal Stadard. PT Derived Fresh or Froze or Lyophilised with good optical clarity. Referece plasma traceable back to IS (ofte by Clauss assay). Recalibrate with chage i Lot umbers 7

8 Coclusios - PT derived Fibrioge assays Cheap ad fast Precise at ormal levels Ca show good agreemet with Clauss i ormal subjects. Ca show good agreemet with Clauss at low levels i DIC ad Hypo fibriogeaemia Referece plasma for calibratio should have good optical clarity Coclusios - PT derived Fibrioge assays Over estimates relative to Clauss i aticoagulat or thrombolytic therapy (relevace?) Shows icreasig divergece from Clauss at elevated levels Ca be iflueced by thromboplasti ad aalyser Oly suitable as a screeig test ( ot recommeded i UK guidelies) Ackowledgmets Diae Kitche Ia Jeigs Tim Woods Eric Presto Isobel Walker UK NEQAS Participats! 8