Blood Productss
Have you ever thought that when you donate blood, with one donation you are actually helping between three or four persons?
This is possible through technological developments and research done years ago men found out that whole blood donation can be separated into different products to make it last longer and be more beneficial.
Thus each donation maybe separated into the following products:-
A) Red Blood Cells
Leucodepleted red cell concentrate
Processed Red cells, filtered and processed to reduce white cells to a minimum as required by European standards.
B) Plasma that which can be further seperated into:-
Filtered Fresh Frozen Plasma
Processed fresh plasma filtered to reduce white cells to a minimum and as conforms to European standards.
or
Filtered Frozen Plasma
Processed plasma filtered to reduce white cells to a minimum and as required by European standards.
C) Pooled Platelets
Processed pool of 5 buffy coats, to produce a pool of filtered platelets, white cell count and platelet cell count as required by European standards
D) Cryoprecipitate
Cryoprecipitate is extracted from the continuous gentle thawing of fresh frozen plasma. This process results in frozen cryoprecipitate in one bag and thawed plasma in other bag
Through other procedures/donations such as plateletphasesis we can produce other products such as:-
Single Donor Platelets
Platelets extracted directly from a donor using aphaeresis equipment. This involves the donor having to stay hooked to this equipment for about 2 hours to produce good quality platelets which would still need to be further processed for optimum quality.
Each of these products have to be stored in different temperatures and have different shelf life.
Definition: A component obtained by removing the majority of leucocytes from a red cell preparation.
Properties: The leucocyte count must be less than 1x106 per unit. Mean count as low as 0.05 x 106 are achievable. Each unit must have a minimum haemoglobin content of 40grms.
Methods of preparation: Various techniques are used to produce this preparation including buffy-coat depletion and filtration. The best results are currently achieved using a combination of both these methods.
Storage: After collection blood should be kept under controlled temperature between 20C and 60C. Temperature should not exceed 100C. Expiry date under these condition depends on the anticoagulant used. Example: using CPDA-1 the storage time is 35 days.
Alternatively, whole blood can be kept up to 24hrs in controlled temperature of between 200C and 240C, before being processed.
Top Filtered Fresh Frozen Plasma
Definition: A component for transfusion prepared either from whole blood or from plasma collected by apheresis, frozen within a period and to a temperature that will maintain the labile coagulation factors functional.
Properties: This preparation contains normal plasma levels of stable coagulation factors, albumin and immunoglobulins. It contains a minimum of 70% of original Factor VIIIc per 100 ml and at least similar quantities of the other labile coagulation factors and naturally occuring inhibitors.
Methods of preparation: Plasma is separated from whole blood collected using a blood bag with integral transfer packs, employing hard spin centrifugation, preferably within 6 hours and not more than 18 hours after collection, if the unit is refrigerated. The plasma is then separated in other transfer bag to be immediately frozen.
Another method is obtaining plasma directly from the donor through apheresis, where the donor is 'connected' to a machine which takes his whole blood, separates the plasma and stores it in a bag, returning back his red cells.
Storage & Stability: The stability on storage is dependent on the storage temperature. Optimal storage temperature is at -250C or lower. Examples:
(a) 36 months storage at temperatures below -250C
(b) 3 months storage at temperatures of -180C to -250C.
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Filtered Frozen Plasma
Definition: A component prepared from plasma by the removal of cryoprecipitate.
Properties: Its contents of albumin, immunoglobulins and coagulation factors is the same as that of fresh frozen plasma, except that the levels of the labile Factors V and VIII are markedly reduced. The fibrinogen concentration is also reduced in comparison to fresh frozen plasma. Should not contain irregular antibodies of clinical significance.
Methods of preparation: Frozen plasma/ cryo-depleted plasma is the by-product of the preparation of cryoprecipitate from fresh frozen plasma.
Storage & Stability: The stability on storage is dependent on the storage temperature. Optimal storage temperature is at -250C or lower. Permitted storage times and temperatures:
(a) 24 months storage at temperatures below -250C.
(b) 3 months storage at temperatures of -180C to -250C.
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Filtered Pooled Platelet Concentrate
Definition: A component derived from fresh whole blood that contains the most of the original platelet content in a therapeutically effective form.
Properties: Depending on the method of preparation, the platelet content per single unit equivalent will vary from 45 to 85 x 109 in 50 to 60 ml suspension medium. Leucocyte content will vary from 0.05 to 1 x 109 and red cells from 0.2 to 1 x 109 per single unit equivalent.
Methods of preparation:
1) Preparation of Platelet rich plasma (PRP): where a unit of fresh whole blood of not more than 24hrs, kept at a temperature between +200C and +240C, is centrifuged so that an optimal number of platelets remain in plasma while the leucocytes and red cells are reduced to a minimum.
2) Preparation of platelets from Platelet rich plasma: Platelets in PRP are sedimented by hard spin centrifugation. The Platelet poor plasma (PPP)/supernatant is removed leaving only 50-70mls of PPP with the platelets concentration. The platelets are allowed to disaggregate and then resuspended.
3) Preparation of platelets from buffy coat: Whole blood stored between +200C to +240C for up to 24 hours is centrifuged so that platelets are sedimented in the buffy coat layer together with the leucocytes. A pool of same blood grouped of 4 to 6 buffycoats are further processed to seperate the platelets from the redcells and leucocytes, filtered and suspended in an additive nutrient solution.
Storage & Stability: Platelets must be stored in plastic bags intended for platelet storage having the characteristic of being permeable to gases for oxygen availability for platelets. During storage pH must remain between 6.8 to 7.4 and they must be continuously agitated in an appropriate equipment, with a temperature of between +200C to +240C . Platelets can be stored for 5 days under the above parameters.
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Cryo precipitate
Filtered Cryo
Definition: A component containing the cryoglobulin fraction of the plasma prepared from Fresh Frozen Plasma.
Properties: Its contents are the major portion of the Factor VIII, von Willebrand factor, fibrinogen, Factor XIII and fibronectin present in freshly drawn and separated plasma.
Methods of preparation: Since the freezing point of cryo is slightly higher then the remaining plasma, Fresh Frozen plasma is slowly thawed at +20C to +60C. The cryo depleted plasma is either extracted immediately during thawing with a siphon method, or if thawing was left overnight a hard spin is necessary before cryo depleted plasma is separated from the cryo precipitate. In any case, Cryo is left as the unmelted (frozen) part in the original FFP bag. Obviously re-labelling is necessary.
Storage & Stability: The stability on storage is dependent on the storage temperature. Optimal storage temperature is at -250C or lower. Permitted storage times and temperatures:
(a) 36 months storage at temperatures below -250C.
(b) 3 months storage at temperatures of -180C to -250C.
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Filtered Single Donor Platelets
Definition: A component obtained by platelet apheresis of a single donor using automated cell separation equipment.
Properties: Depending on method and equipment used, each procedure should give a platelet yield from 200 to 800 x 109 Leucocytes and red cells should also be minimal although much depends on method an equipment used. SDP provides the advantage of collecting platelets from selected donors, to reduce risk of HLA alloimmunisation and for effective treatment of patients already alloimmunised. Reducing the number of donor exposures also reduces risks of viral transmisson.
Methods of preparation: Platelets extracted directly from the donor using an apheresis equipment. This involves the donor having to stay hooked to this equipment for about 2 hours to produce good quality platelets which would still need to be further processed for better quality.
Storage & Stability: Platelets must be stored in plastic bags intended for platelet storage having the characteristic of being permeable to gases for oxygen availability for platelets. During storage pH must remain between 6.8 to 7.4 and they must be continuously agitated in an appropriate equipment, with a temperature of between +200C to +240C. Platelets under the above parameters can be stored for 5 days.
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