Asian Journal of Transfusion Science
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Year : 2011  |  Volume : 5  |  Issue : 2  |  Page : 175-176
White particulate matter in a packed red blood cells unit

Department of Transfusion Medicine, PGIMER, Chandigarh, India

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Date of Web Publication28-Jul-2011

How to cite this article:
Sachdev S, Dhawan HK, Khetan D, Marwaha N, Jain A, Sharma RR. White particulate matter in a packed red blood cells unit. Asian J Transfus Sci 2011;5:175-6

How to cite this URL:
Sachdev S, Dhawan HK, Khetan D, Marwaha N, Jain A, Sharma RR. White particulate matter in a packed red blood cells unit. Asian J Transfus Sci [serial online] 2011 [cited 2023 Jan 28];5:175-6. Available from:

   Introduction Top

Aggregate formation in blood units has been known since long. Particulate matter visible to naked eye, white in color, has been described in detail by Rentas et al. [1] White particulate matter (WPM) in blood bags is reported to be composed of normal blood elements, namely aggregates of platelets, with variable amounts of fibrin and trapped red and white cells and not of extraneous material or organisms. [2]

Enhanced visual inspection has been implemented by American Red Cross [1] for the observation of WPM at all the blood transfusion centers. Under this, the blood bag is kept with the labeled side down on flat surface, undisturbed for 10 minutes. At our department, we are issuing blood units after strict visual inspection as per the departmental standard operating procedure (SOP). We recently encountered one packed red blood cell (PRBC) unit having WPM. There are no clear guidelines regarding the transfusion of WPM containing blood units. Looking at the sensitivity of the issue and the ill effects that can be associated with transfusion of such units, we thought that the information should be shared with other staff involved in issue of blood units.

   Observation Top

Many small and few large white particles [Figure 1] were observed on day 1 in a nonleucoreduced PRBC unit. This was prepared from 450 ml whole blood with CPDA-1 anticoagulant utilizing soft spin. The blood donor's investigation revealed normal serum protein, triglyceride, and cholesterol. Complete blood counts including platelet count were also within normal limits. Donor was not on any medication prior to the blood donation. Leishman stained smears from the WPM showed only granular material. Blood culture was sterile.
Figure 1: PRBC unit depicting many small and few large white particulate matter

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   Pathophysiology of event Top

Mechanisms that predispose to WPM formation are not clear, but high platelet counts, lipemia, and use of hard spin during component preparation can all favor the formation. [1],[2] Swank [3] reported that high pressures were necessary to force stored whole blood through a filter and increase in pressure correlates with increase in storage time. He attributed this to formation of compact aggregates of platelets and white blood cells due to increased adhesiveness during routine storage of blood, and therefore, was responsible for increased filter occlusion. Reiss et al., [4] reported that the rate of flow of platelet-rich blood units was almost half as compared to platelet-poor red cell units. They attributed this finding to a higher microaggregate content found in 170 μm pore filters when platelet-rich units were filtered. Robertson et al., [5] observed macroaggregates in up to 85% of additive red-cell units stored for 28 days. The formation of WPM is removed by leucoreduction and removal of platelets from whole blood. [1],[2]

   Clinical implications Top

The latest update on the United States Food and Drug administration does not conclusively rule out a potential association between particulate formation in blood units and some adverse events. [2],[6] Therefore, such an appearance should call for detailed investigations including culture of the implicated blood units and their quarantine till the investigation reports ascertain the normal findings.

   References Top

1.Rentas FJ, Macdonald VW, Rothwell SW, McFaul SJ, Asher LV, Kennedy AM, et al. White particulate matter found in blood collection bags consist of platelets and leukocytes. Transfusion 2004;44:959-66.  Back to cited text no. 1
2.Update on Particulate Matter in Blood Bags. Available from: . [Last accessed on 2011 Jun 20].   Back to cited text no. 2
3.Swank RL. Alteration of blood on storage: Measurement of adhesiveness of "aging" platelets and leukocytes and their removal by filtration. N Engl J Med 1961;265:728-33.  Back to cited text no. 3
4.Reiss RF, Katz AJ. Microaggregate content and flow rates of packed red blood cells. Transfusion 1977;17:484-9.  Back to cited text no. 4
5.Robertson M, Boulton FE, Doughty R, Maclennan JR, Collins A, McCelland DB, et al. Macroaggregate formation in optimal additive red cells. Vox Sang 1985;49:259-66.  Back to cited text no. 5
6.Iwamoto M, Curns AT, Blake PA, Jernigan DB, Holman RC, Lance-Parker SE, et al. Rapid evaluation of risk of white particulate matter in blood components by a statewide survey of transfusion reactions. Transfusion 2004;44:967-72.  Back to cited text no. 6

Correspondence Address:
Suchet Sachdev
Department of Transfusion Medicine, PGIMER, Chandigarh - 160 012
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0973-6247.83247

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2006 - Asian Journal of Transfusion Science | Published by Wolters Kluwer - Medknow
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