1、Designation: F2382 18Standard Test Method forAssessment of Circulating Blood-Contacting Medical DeviceMaterials on Partial Thromboplastin Time (PTT)1This standard is issued under the fixed designation F2382; the number immediately following the designation indicates the year oforiginal adoption or,
2、in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the screening of circulatingblood-contacting device mater
3、ials for their ability to induceblood coagulation via the intrinsic coagulation pathway. Thisassay should be part of the hemocompatibility evaluation fordevices and materials contacting human blood, as per ANSI/AAMI/ISO 10993-4.1.2 All safety policies and practices shall be observedduring the perfor
4、mance of this test method.1.3 All plasma and any materials that had contact withplasma will be bagged in a biohazard bag, properly labelledwith the contents, and disposed of by appropriate means. Theplasma should be handled at the Biosafety Level 2 as recom-mended in the Centers for Disease Control/
5、National Institutesof Health Manual Biosafety in Microbiological Laboratories.1.4 The normal pooled human plasma must have testednegative for Hepatitis B (HBV) or Human Immunodeficiency(HIV) viruses. The plasmas should be treated like any patientplasma using standard precautions. The plasma should b
6、ehandled at the Biosafety Level 2 as recommended in theCenters for Disease Control/National Institutes of HealthManual Biosafety in Microbiological Laboratories.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.6 This standa
7、rd does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.7 This inter
8、national standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) C
9、ommittee.2. Referenced Documents2.1 ANSI/AAMI Standard:ANSI/AAMI/ISO 10993-4 Biological Evaluation of MedicalDevicesPart 4: Selection of Tests for Interactions withBlood22.2 Other Document:U.S. Department of Health and Human Services Biosafety inMicrobiological and Biomedical Laboratories (BMBL),5th
10、 ed., 199933. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 activatora medical material which demonstrates ashortened clotting time; an initiator of the intrinsic coagulationpathway.3.1.2 partial thromboplastin time (PTT) assaya modifica-tion of the Activated Partial Thrombopla
11、stin Time (APTT)assay; unlike the APTT test, the PTT assay uses a reagent(rabbit brain cephalin) without activating substances such assilica, kaolin, elagic acid. The material being tested acts as theactivator.3.1.3 read timethe time during which data is collected todetect a clot.3.1.4 blank timea p
12、eriod at the beginning of an assaywhen no data is taken. This is done to eliminate interferencefrom premixing reagents, bubbles, and so forth.3.1.5 equilibration timethe time allowed for the plasmasamples to warm to 37C. The coagulation analyzer can be setto zero if samples are pre-warmed to this te
13、mperature.3.1.6 duplicate flagthe agreement between the results ofduplicate samples in percent. For example, if set to “15,” thedifference between the two channels must be less than or equal1This test method is under the jurisdiction of ASTM Committee F04 on Medicaland Surgical Materials and Devices
14、 and is the direct responsibility of SubcommitteeF04.16 on Biocompatibility Test Methods.Current edition approved Oct. 1, 2018. Published October 2018. Originallyapproved in 2004. Last previous edition approved in 2017 as F2382 171. DOI:10.1520/F2382-18.2Available from American National Standards In
15、stitute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.3The BMBL 5th Edition (December 2009) is available from the GovernmentPrinting Office or https:/www.cdc.gov/biosafety/publications/bmbl5/bmbl.pdfCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Con
16、shohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade O
17、rganization Technical Barriers to Trade (TBT) Committee.1to 15 %. If the variance in clot times exceeds this percentage,an asterisk “*” will be printed by the average results on thereport.4. Significance and Use4.1 The purpose of this test method is to determine the timecitrated plasma exposed to me
18、dical materials takes to form aclot when exposed to a suspension of phospholipid particlesand calcium chloride. In this test method, the test article is theactivator. The PTT assay is a general screening test for amedical materials ability to activate the intrinsic coagulationpathway. Material sampl
19、es that show a shortened PTT areactivators of the intrinsic coagulation pathway.4.2 The test article, reference materials, and controls areexposed to human plasma. The plasma is tested on a coagula-tion device. Each sample tube is assayed in duplicate. Theresults are reported as a percentage of the
20、negative control.5. Apparatus5.1 Polypropylene Test Tubes with Caps, 12 by 75 mm.5.2 Automatic Pipets and Tips, 100 and 1000 L.5.3 Ice Bath.5.4 Coagulation Analyzer qualified, see A1.1.5.5 Agitating Water Bath, 37 6 2C, capable of 60 rpm.5.6 Coagulation Analyzer Cuvettes, or equivalent for spe-cific
21、 analyzer.6. Reagents and Materials6.1 Calcium Chloride, 25 mM.6.2 Citrated Human Blood Plasma, fresh (less than 4 h fromdraw) or freshly-frozen, maintained at minus 80C, pooled.6.3 Lyophilized Rabbit Brain Cephalin (RBC).6.4 Positive Reference Material (Optional), see A1.2.6.5 Positive Control, gla
22、ss (Pasteur pipette tips or glassbeads). Other qualified positive control materials such asBuna-N-Rubber may be selected once they have demonstrateda consistent thrombogenic response.6.6 Negative Reference Material (e.g. High DensityPolyethylene, HDPE).6.7 Marketed Comparator Device (Optional). A le
23、gallymarketed, clinically acceptable device that has similar bloodcontact nature and clinical use as the material/device beinginvestigated.NOTE 1It may be helpful to use a positive reference control material(n=1) per assay to assure continuity between runs.7. Hazards7.1 The human blood plasma should
24、 be treated like anypatient plasma using standard precautions. The plasma shouldbe handled at the Biosafety Level 2 as recommended in the USDepartment of Health and Human Services Biosafety inMicrobiological and Biomedical Laboratories.8. Preparation of Apparatus8.1 Prepare each test article, the ne
25、gative referencematerials, marketed comparator device (if used) and controls intriplicate. If a positive reference control material is used, asingle replicate is acceptable. All samples are prepared basedon a ratio of either 4 or, preferably 6 cm2of material to 1 mLplasma and placed into polypropyle
26、ne tubes. For devicetesting, if test sample quantity allows, use three separatedevices; otherwise, take three representative samples from onedevice.8.2 Label duplicate polypropylene tubes and place in the icebath.8.3 Turn on the coagulation analyzer and allow it to warmup to 37 6 2C and equilibrate
27、for at least 10 min.8.4 Program the analyzer to test under the APTT functionwith an equilibration time of 60 s, activation time of 120 s, a| blank time of 14 s, and a read time of 286 s.8.5 Pre-warm analysis cuvettes (or cups, depending onanalyzer selected) at 37 6 2C.8.6 Pre-warm calcium chloride a
28、t 37 6 2C.8.7 Rabbit Brain Cephalin (RBC) Preparation:8.7.1 Allow the RBC to come to room temperature.8.7.2 Reconstitute the RBC as indicated by the RBC reagentmanufacturer.8.7.3 Place in an agitating water bath set at 37 6 2C and 60rpm for 15 min to ensure complete rehydration of contents.8.7.4 Vor
29、tex 15 s after rehydration is complete.8.7.5 Place at 37 6 2C.8.8 If using frozen blood plasma, quick thaw the plasma at37 6 2C and place on ice immediately.9. Procedure9.1 The test material(s), reference material(s), marketedcomparator device (if used) and controls are placed intopolypropylene tube
30、s and exposed to the appropriate quantity ofplasma, based on a ratio of 4 cm2, or preferably 6 cm2ofmaterial to 1 mL plasma. The negative control is a polypro-pylene tube with 1 mL of plasma, without additional material.9.2 The samples are exposed to the plasma for 15 6 1 minina376 2C agitating wate
31、r bath at 60 rpm.9.3 After 15 min of incubation, the tubes are immediatelyplaced into the ice bath and immediately transferred intopre chilled new polypropylene tubes.9.4 Vortex each sample 15 s before each use/run.9.5 Avoiding bubbles, transfer 100 L of the plasma intopre-warmed cuvettes and allow
32、the plasma to equilibrate for 60sat376 2C.9.6 To each cuvette/cup, add 100 L warmed RBCpreparation, initiating the 2 min activation step. (Invert RBC tomix prior to each use.)9.7 After activation, add 100 L warmed 25 mM calciumchloride to each cuvette.F2382 1829.8 Allow the analyzer to read the samp
33、le for the formationof clots (up to 5 min).9.9 Record the clotting time (seconds) for each sample, aswell as the average clotting time of the duplicate samples.NOTE 2The volume of plasma, RBC reagent, and calcium chlorideneeded for the clotting time measurement may vary with differentanticoagulation
34、 analyzers. It is acceptable to use a plasma volume that isspecific to the coagulation analyzer used, as long as the plasma to reagentratio remains 1:1.10. Calculation or Interpretation of Results10.1 Calculate the test sample result (% negative control)for test material, reference, and positive con
35、trol sample mean.% negative control5 (1)Average clotting time s! of sampleAverage clotting time s! of negative control3 10010.2 Statistical Analysis of Results:10.2.1 The mean and standard deviation for each group ofplasma: test article, negative control, positive control, andpositive and/or referen
36、ce material controls are calculated.10.2.2 The values for the test article, negative control,positive control, negative and/or positive reference material,marketed comparator device results are compared to each otherwith Analysis of Variance (ANOVA) including post-hoc pair-wise comparisons such as a
37、 Tukey or Newman-Keuls test.10.2.3 Differences shall be considered statistically signifi-cant if the p-value is less than 0.05. The test article isconsidered to pass the PTT test if there is no statisticaldifference between the test article and the negative control(untreated plasma) or the negative
38、reference material control. Ifthe test article result is statistically significantly lower thanboth the negative control (untreated plasma) and the negativereference material control, a comparison between the testarticle and a marketed comparator device would help todetermine whether the test device
39、/material is likely to beclinically acceptable or not.10.2.4 The positive control and the positive reference ma-terial control (if used) results, expressed as percent negativecontrol (untreated plasma), must generally be 85 %. Thenegative reference material control result, expressed as percentnegati
40、ve control (untreated plasma), must be 80 %. If theassay does not meet this specification, the experiment is to berepeated until the controls meet these specifications.10.2.5 The Coefficient of Variation (CV) between the dupli-cates for each sample must be 15 %. The duplicates of eachtest article sa
41、mple are averaged and one value is reported as theclotting time. This results in three clotting time values for eachtest article. The three values are then averaged to report a finalaverage clotting time of the test article. The values for each testarticle sample must be within 625 % of this average
42、. If thevalues are greater than 25 % of the average of the run, theexperiment needs to be repeated.11. Precision and Bias11.1 The precision and bias of this test method has not yetbeen determined.12. Keywords12.1 blood coagulation; blood compatibility; partial throm-boplastin time; PTTANNEX(Mandator
43、y Information)A1. VENDOR INFORMATIONA1.1 Coagulation AnalyzerAble to reliably detect clotformation, with a maximum clot detection time greater than300 s.A1.2 Reference Control MaterialNatural latex tubing orblack rubber stopper. Alternate reference materials may beselected, once they have demonstrat
44、ed a consistent, thrombo-genic response. More than one reference material may be used.F2382 183APPENDIX(Nonmandatory Information)X1. RATIONALEX1.1 This test method allows assessment of medical devicematerials ability to induce blood coagulation via the intrinsiccoagulation pathway. It should be part
45、 of the hemocompatibil-ity evaluation for devices and materials contacting humanblood.REFERENCES(1) Sawyer, A., “In Vitro Hemocompatibility Screening Method forBiomaterials,” World Congress for Biomaterials MeetingTransactions, 1992, p. 669.(2) U.S. Department of Health and Human Services Biosafety
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