Asian Journal of Transfusion Science
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White thrombus “fibrin” in the blood bag

 Department of Transfusion Medicine and Pathology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India

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Date of Submission07-Jul-2021
Date of Acceptance20-Feb-2022
Date of Web Publication26-Sep-2022

How to cite this URL:
Gnanaraj J, Nadeem N, Toora E, Basu D, Basavarajegowda A. White thrombus “fibrin” in the blood bag. Asian J Transfus Sci [Epub ahead of print] [cited 2023 Mar 24]. Available from:

We report the formation of a whitish membranous “fibrin” thrombus in a 350 ml Terumo quadruple blood bag. The blood bag used for the collection was within the expiry date and was stored under ideal conditions. There were no signs of any manufacturing defects or any abnormalities detected in the appearance of the blood bag or the needle. The anticoagulant inside the blood bag was clear. The donation was from a 38-year-old healthy male donor with no comorbidities. Labeling of blood bag and phlebotomy were done as per the departmental standard operating procedure (SOP).[1] The blood-collection process was uneventful, and 350 ml of whole blood was collected within 10 min of needle prick with no local or systemic donor reactions. There was no evidence of any under- or over-collection. An automated blood-collection monitor was not used during the blood-collection process, and manual kneading of the blood bag was done. Once collected, the blood bag was shifted immediately to the component laboratory for separation. The blood bag was separated into packed red blood cells, plasma, and buffy coat layers using heavy spin. When separating the components into satellite bags using the Terumo Automatic Component Extractor II, a clot in the blood bag prevented transferring the buffy coat from the primary blood bag. The blood bag was cut open, and a large membranous white thrombus measuring about 8.5 cm × 4 cm × 0.5 cm was found [Figure 1]a and [Figure 1]b. The specimen was sent for histopathological examination, which confirmed fibrin [Figure 1]c and [Figure 1]d.
Figure 1: (a) Whitish membranous fibrin thrombus. (b) Blood clot with adjacent fibrin thrombus. (c) Histopathological section showing thrombus formation with entrapped red blood cells and fibrin. (d) Section showing thin fibrin strands with an occasional aggregate of lymphocytes

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After ruling out the various factors that can influence clot formation in a blood bag, as shown by Shastry et al.,[2] we found that the most likely cause of this white thrombus formation can be explained by the improper manual mixing of the blood bag with the anticoagulant and potential fluctuations in the rate of blood flow. The blood bag manufacturer recommends that the bag be manually agitated gently every 45 s during the collection process. Although blood-collection monitors may reduce the need to attend to the blood-collection bag due to automated agitation, they are expensive and might not be available at every blood center. Further, studies have shown that there might not be any added advantage of automated mixing devices compared to manual mixing.[3],[4] Due to the unavailability of a blood-collection monitor, the blood flow rate during the collection process could not be monitored.

Blood is a fragile tissue that changes once it is removed from the body. Virchow's triad suggests that the triad of blood chemistry, blood-contacting surface, and flow regimen affects blood flow.[5] One of the many significant factors influencing thrombus formation is the rate of blood flow rate. When the blood flow is sluggish, polymeric materials such as the “thrombogenic” blood bag might be associated with blood clotting. The initial attachment of platelets to artificial surfaces increases with increasing flow or shear rate. Under low shear rate during venous flow, fibrin formation is abundant. The rate and the extent of clot formation in vitro are also affected by the chemical composition of the substrate, as well as the physical circumstances, such as flow rate, space width, and surface energy.[6] Overall, all these factors led to the formation of thrombus containing red cells entrapped in the fibrin mesh, which resembles whole coagulated blood [Figure 1]b.

In conclusion, due to improper mixing and possible flow rate fluctuations, the blood-contacting surface could have been the nidus triggering platelet aggregation and coagulation cascade, resulting in fibrin formation. Blood clots leading to fibrin formation in a blood-collection bag could obstruct the blood component separation bringing about wastage of the blood components. Therefore, adequate measures were taken, and reinforcement of the SOP was done, ensuring that adequate mixing of the blood bag takes place during the blood-collection process and similar incidents do not reoccur.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.

   References Top

National AIDS Control Organization (NACO), Ministry of Health and Family Welfare. Standards for Blood Banks and Blood Transfusion Services. London, UK: National AIDS Control Organization (NACO), Ministry of Health and Family Welfare; 2007.  Back to cited text no. 1
Shastry S, Das S. Root-cause analysis for clot in blood bag. Asian J Transfus Sci 2016;10:3-4.  Back to cited text no. 2
[PUBMED]  [Full text]  
de Korte D, Veldman HA. Automated blood-mixing devices still fail to mix at low bleeding rates. Vox Sang 2001;80:34-9.  Back to cited text no. 3
Folléa G, Bigey F, Jacob D, Cazenave JP. Comparative validation of manual and automated methods for mixing and volume control of total blood samples. Transfus Clin Biol 1997;4:391-402.  Back to cited text no. 4
Ratner BD, Horbett TA. Evaluation of blood-materials interactions. In: Ratner BD, Hoffman AS, Schoen FJ, Lemons JE, editors. Biomaterials Science: An Introduction to Materials in Medicine. 3rd ed. London, UK: Elsevier; 2013. p. 617-34.  Back to cited text no. 5
Vroman L. When Blood Is Touched. Materials (Basel). 2009;2:1547-57. doi: 10.3390/ma2041547. PMCID: PMC5513385.  Back to cited text no. 6

Correspondence Address:
Abhishekh Basavarajegowda,
Department of Transfusion Medicine, Room No. 5042, Superspeciality Block, Puducherry
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ajts.ajts_91_21


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