What is a unit?

Gorlin, Jed B.; Cable, Ritchard G.

doi:10.1046/j.1537-2995.2000.40030263.x

Cited by 13 publications

(18 citation statements)

References 10 publications

(9 reference statements)

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“…Other than specifying the volume of blood to be collected from a donor, current standards do not address the Hb content of a RBC unit after processing. A transfused patient may therefore, unknown to the transfusing physician, receive RBC units that vary within wide limits 27,28 . A major cause for this variation is the donor's Hb concentration, which may range between 125 and 165 g per L. Even though the volume of blood collected is standardized at 450 mL within narrow limits, the total RBC Hb can range from 56 to 74 g. Furthermore, during the subsequent preparation of the final RBC unit, substantial losses may also occur.…”

Section: Hb Contentmentioning

confidence: 99%

Red blood cells intended for transfusion: quality criteria revisited

Högman

Meryman

2005

Transfusion

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Great variation exists with respect to viability and function of fresh and stored red blood cells (RBCs) as well as of the contents of RBC hemoglobin (Hb) in individual units. Improved technology is available for the preparation as well as the storage of RBCs. The authors raise the question whether it may be time to revise current standards for RBC units. The establishment of a standard unit of blood based on Hb content should be a high-priority goal. It is recommended that a standard RBC unit should contain 50 g of Hb. Major organizations concerned with the collection and distribution of blood components should agree on the criteria for a standard unit of RBCs based on Hb content and for the collection of double units. Manufacturers of blood collection equipment should provide suitable technology for collecting a standard unit with defined contents of RBC Hb. Efforts should be directed at the design of storage solutions acceptable for transfusion that maximize the maintenance of both RBC viability and function during storage. The ideal storage protocol would require sterile, high-pH solutions containing both glucose and electrolytes.

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Section: Hb Contentmentioning

confidence: 99%

Red blood cells intended for transfusion: quality criteria revisited

Högman

Meryman

2005

Transfusion

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“…It is evident that 405 mL blood collected from a donor with Hct of 40% will contain fewer red cells than 495 mL from a donor with Hct of 48%. Indeed, there is much debate about what constitutes 'a unit' of red cells, what the minimum Hb content of 'a unit' should be and whether the standardized limit should be the same for units derived from whole blood and by apheresis (Gorlin & Cable, 2000).…”

Section: Current Technologymentioning

confidence: 99%

Automated red cell collection – quality and value

Harrison

2006

Transfusion Medicine

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Automated red cell collection was initially used largely for therapeutic purposes. New technology has rendered the procedure safer for donors and easier for machine operators. Optimal additive solution can be automatically added and the red cells filtered to provide a leucodepleted product. Two units of red cells may be collected during a single procedure from individuals who have a high enough red cell mass, whilst a single unit of red cells plus platelets or plasma can be collected from smaller donors. In vitro studies suggested that red cells collected by automated methods would be of better quality than those collected by gravity. This was not confirmed in vivo, but red cells collected by automated methods have the major advantage of consistency in terms of haemoglobin content, volume and haematocrit, compared with red cells collected by gravity. This standardised product is of particular value for transfusion dependent patients as the patient's haemoglobin can be maintained within narrow limits. The use of a double dose red cell product for transfusion to a single patient also confers benefit in terms of reduction in donor exposure.

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“…A whole‐blood donation may range from 405 to 550 mL 1 . As noted by Gorlin and Cable, 2 this range results in an almost twofold variability in RBC content, from 154 to 275 mL. We have very limited information on the actual RBC content of units in current use.…”

mentioning

confidence: 95%

“…Vascular volume, concomitant intravenous fluid administration, renal failure, and splenomegaly all affect RBC transfusion response. Accounting just for vascular volume, transfusion of a minimum volume unit from a donor with a Hct level of 38 percent to a 100‐kg man would result in an expected Hct increase of just 2 percent, whereas transfusion of a large unit from a donor with a 50 percent Hct level to a 50‐kg woman would cause a 9 percent increase 2 . The effect of storage senescence can magnify these differences.…”

mentioning

confidence: 99%

Blood components should be labeled for content

Davenport¹

2004

Transfusion

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What is a unit?

Cited by 13 publications

References 10 publications

Red blood cells intended for transfusion: quality criteria revisited

Red blood cells intended for transfusion: quality criteria revisited

Automated red cell collection – quality and value

Blood components should be labeled for content

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