International Journal of Laboratory Hematology The Official journal of the International Society for Laboratory Hematology
ORIGINAL ARTICLE
INTERNAT IONAL JOURNAL OF LABORATO RY HEMATO LOGY
Effects of storage and thawing conditions on coagulation testing R. C. GOSSELIN, K. HONEYCHURCH, H. J. KANG, D. M. DWYRE
Pathology and Laboratory Medicine, Davis Health System, University of California, Sacramento, CA, USA Correspondence: R. C. Gosselin, Pathology and Laboratory Medicine, University of California, Davis Health System, University of California, Davis Health System, 2315 Stockton Blvd, Room 2P344, Sacramento, CA, USA. Tel.: +916-703-6688; Fax: +916-703-6775; E-mail: [email protected]
doi:10.1111/ijlh.12342
Received 18 November 2014; accepted for publication 2 February 2015 Keywords Coagulation, laboratory practice
S U M M A RY Introduction: Current recommendations for coagulation testing storage and thawing are based on historical studies that were performed using unbuffered 3.8% sodium citrate. We sought to measure the effects of freezing and thawing conditions 3.2% buffered sodium citrate plasma samples that have been stored in vials with either snap or sealed screw tops, frozen in 70 °C freezer or dry ice and thawed either capped or uncapped. Methods: Shed blood samples were pooled and then aliquoted into four snap top and four screw tops vials. Half the vials were stored in a 70 °C freezer, and half on dry ice for at least 16 h. Afterwards, half the frozen samples were thawed in 37 °C waterbath capped, and other half were thawed capped. After thawing cycles, samples were tested for PT, activated partial thromboplastin time (APTT), fibrinogen, D-dimer, factor assays, von Willebrand factor activity, plasminogen, antithrombin, protein C and lupus anticoagulant. Results: Prothrombin time, APTT, factor X, and lupus anticoagulant testing were affected by all vials, freezing and thawing conditions, whereas fibrinogen, D-dimer, von Willebrand activity or protein C were not affected by any vial, freezing or storage condition. Conclusions: Storage vials, freezing and thawing condition affect coagulation testing, although these differences may not be clinically significant.
INTRODUCTION The current recommendations for processing blood specimens for coagulation have recently been updated by the Clinical and Laboratory Standards Institute (CLSI) indicating the stability for PT is 24 h and for activated partial thromboplastin time (APTT) is 4 h (unless assessing for unfractionated heparin anticoagulation, whereas the test should be performed within 2 h of collection) or an artificial reduction in factor © 2015 John Wiley & Sons Ltd, Int. Jnl. Lab. Hem. 2015, 37, 551–559
activity may occur [1]. The British Committee for Standards in Haematology (BCSH) also published guidelines for coagulation testing providing more detail for storage, including use of screw-cap polypropylene vials with ‘o’ ring caps [2]. Samples that cannot be tested within the recommended limit time frame should be frozen to maintain sample integrity [1–4]. The CLSI and BCSH both recommend shortterm storage (
ORIGINAL ARTICLE
INTERNAT IONAL JOURNAL OF LABORATO RY HEMATO LOGY
Effects of storage and thawing conditions on coagulation testing R. C. GOSSELIN, K. HONEYCHURCH, H. J. KANG, D. M. DWYRE
Pathology and Laboratory Medicine, Davis Health System, University of California, Sacramento, CA, USA Correspondence: R. C. Gosselin, Pathology and Laboratory Medicine, University of California, Davis Health System, University of California, Davis Health System, 2315 Stockton Blvd, Room 2P344, Sacramento, CA, USA. Tel.: +916-703-6688; Fax: +916-703-6775; E-mail: [email protected]
doi:10.1111/ijlh.12342
Received 18 November 2014; accepted for publication 2 February 2015 Keywords Coagulation, laboratory practice
S U M M A RY Introduction: Current recommendations for coagulation testing storage and thawing are based on historical studies that were performed using unbuffered 3.8% sodium citrate. We sought to measure the effects of freezing and thawing conditions 3.2% buffered sodium citrate plasma samples that have been stored in vials with either snap or sealed screw tops, frozen in 70 °C freezer or dry ice and thawed either capped or uncapped. Methods: Shed blood samples were pooled and then aliquoted into four snap top and four screw tops vials. Half the vials were stored in a 70 °C freezer, and half on dry ice for at least 16 h. Afterwards, half the frozen samples were thawed in 37 °C waterbath capped, and other half were thawed capped. After thawing cycles, samples were tested for PT, activated partial thromboplastin time (APTT), fibrinogen, D-dimer, factor assays, von Willebrand factor activity, plasminogen, antithrombin, protein C and lupus anticoagulant. Results: Prothrombin time, APTT, factor X, and lupus anticoagulant testing were affected by all vials, freezing and thawing conditions, whereas fibrinogen, D-dimer, von Willebrand activity or protein C were not affected by any vial, freezing or storage condition. Conclusions: Storage vials, freezing and thawing condition affect coagulation testing, although these differences may not be clinically significant.
INTRODUCTION The current recommendations for processing blood specimens for coagulation have recently been updated by the Clinical and Laboratory Standards Institute (CLSI) indicating the stability for PT is 24 h and for activated partial thromboplastin time (APTT) is 4 h (unless assessing for unfractionated heparin anticoagulation, whereas the test should be performed within 2 h of collection) or an artificial reduction in factor © 2015 John Wiley & Sons Ltd, Int. Jnl. Lab. Hem. 2015, 37, 551–559
activity may occur [1]. The British Committee for Standards in Haematology (BCSH) also published guidelines for coagulation testing providing more detail for storage, including use of screw-cap polypropylene vials with ‘o’ ring caps [2]. Samples that cannot be tested within the recommended limit time frame should be frozen to maintain sample integrity [1–4]. The CLSI and BCSH both recommend shortterm storage (
