Accumulation of DI-2-Ethylhexyl Phthalate (DEHP) in Whole Blood, Platelet Concentrates, and Platelet-Poor Plasma

The concentration of the plasticizer, di-2-ethylhexyl phthalate (DEHP), in the plasma was measured after storage of the whole blood in polyvinylchloride plastic bags at 4 C for up to 38 days in either ACD or CPD. The plasma from ACD-stored whole blood contained more DEHP than that from CPD-stored whole blood. The continuous-flow centrifugation washing procedures removed about 98 per cent of the DEHP from ACD whole blood stored for 33 days at 4 C.
DEHP was assayed in the platelet-rich plasma, platelet-poor plasma, supernatant of the platelet concentrate, washed platelets, and washed red blood cells prepared from CPD whole blood. Very little DEHP was found in the washed red blood cells and platelets, a small amount was found in the platelet-poor plasma, and a large amount in the supernatant of the platelet concentrate. A greater amount of DEHP accumulated in the platelet concentrates that were stored at 22 C than in those stored at 4 C. When platelet concentrates from CPD whole blood were stored at 22 C for 72 hours, the amount of DEHP was about four times that observed after 4 C storage for the same length of time.     

Exchange Transfusion with ACD‐Adenine Blood. A Follow‐up Study

Twenty‐seven children had received neonatal exchange transfusions (one to seven times) with ACD‐adenine red cell concentrate containing 7 mg adenine per 100 ml of blood. They were evaluated in a follow‐up study at about five years of age. The examination comprised a history and physical examination, routine blood and urine examination, urine culture, serum creatinine and pitressin test. In no case could any renal damage be demonstrated. No correlation was found between the number of transfusions with ACD‐adenine blood and the values of serum creatinine and pitressin test.     

Circulation of Concentrated One‐day‐old Platelets in Vivo

Platelet concentrates of rat and human origin were stored at 22 C or at 4 C for up to 24 hours without additives. Transfusion of these concentrates into thrombocytopenic recipients demonstrated that: (1) storage of rat or human platelets at 4 C for up to 24 hours did not affect their recovery in vivo ; (2) storage at 22 C resulted in a marked reduction in the viability of rat platelets but only a slight reduction in the viability of human platelets as adjudged by these criteria; (3) at 24 hours posttransfusion, the residual increment of platelets stored at 22 C was significantly higher than that of platelets stored at 4 C. The pH of the concentrates (rat and human) stored at 4 C remained slightly alkaline while the pH of those stored at 22 C., especially rat platelets, was significantly reduced. The deleterious effects of storage of platelets at 4 C are well known. These effects, however, do not preclude their usefulness when a limited objective of arresting or preventing hemorrhage for short periods is pursued. When daily platelet transfusions are feasible, platelets stored for 24 hours at 4 C in the absence of fresh material are adequate for clinical use.     

Suppression of Primary Rh‐immunization by Anti‐Rh

A case is reported in which passively acquired antibody (RhoGAM®) apparently prevented maternal immunization to Rh by a large volume of Rh‐positive blood. After a 1,000‐ml transfusion of Rh‐positive blood into an Rh‐negative mother, 59 ml of Rh‐immune globulin were administered in fractional doses at 12‐hour intervals for eight days. During this time, tests for evidence of mixed agglutination, direct and indirect antiglobulin tests, and the hematocrit value were used to monitor patient response. The dose of Rh‐immune globulin administered (17,700 μg), as well as the ratio of Rh antibody (μg) to volume (ml) of administered blood, was 18 to 1, the highest thus far reported, but adverse effects were not noted.     

Behavior of Previously Frozen Erythrocytes Used during Open‐heart Surgery

Glycerolized human red blood cells that had been stored in the frozen state at ‐80 C up to six months, thawed, and washed by the dilution‐agglomeration procedure of Huggins, were administered during extracorporeal circulation along with nonfrozen acid‐citrate‐dextrose‐(ACD) stored blood. Eleven patients who received both nonfrozen ACD‐stored blood and the previously frozen, washed, concentrated cells were compared with 14 patients who were given whole blood stored only in ACD. No significant differences were observed between the two groups in respect to platelet count, partial thromboplastin time, prothrombin time, or fibrinogen level. Higher plasma and urine hemoglobin levels were observed in the patients who received both blood stored in ACD and washed, previously frozen, concentrated red blood cells. Hemoglobinuria was observed in both groups but was not accompanied by significant differences in BUN or creatinine levels. There was no significant difference in morbidity or mortality between the two groups of patients.     

Preservation of Red Blood Cell 2,3‐Diphosphoglycerate in Stored Blood Containing Dihydroxyacetone

In a search for red blood cell metabolites which would preserve 2,3‐DPG during storage of blood, it was discovered that dihydroxyacetone (DHA) prolonged the maintenance of 2,3‐DPG levels for up to four weeks of storage, compared to about one week for presently used preservatives such as CPD. Four‐week preservation of 2,3‐DPG at normal levels was desired. CPD‐adenine was used as the starting point and a formulation having a pH of 7.0 and a DHA concentration of 20 millimoles per liter of blood was developed. The 2,3‐DPG level at four weeks of storage was proportional to DHA concentration in the 5 to 20 mM range. The osmotic fragility, red blood cell ATP levels, and plasma sodium, potassium, and hemoglobin during four weeks of storage in CPD‐adenine‐DHA were similar to those in blood stored in CPD‐adenine.     

Therapeutic Effectiveness of Homologous Erythrocyte Transfusions Following Frozen Storage at ‐80 C for up to Seven Years

Cohn‐processed red blood cells that had been stored for as long as seven years at ‐80 C., washed by the ADL procedure and then stored at 4 C for up to 48 hours, showed approximately 90 per cent 24‐hour recovery in vivo by an automated differential agglutination (ADA) technic, recovery in vitro of approximately 90 per cent, and an index of therapeutic effectiveness of approximately 80 per cent. Washing Huggins‐preserved red blood cells with EDTA by the Huggins process produced a significant deterioration (decreased 24‐hour posttransfusion survival and decreased recovery in vitro ) following storage at ‐80 C for as long as three years. In two of seven patients studied the Huggins‐processed red blood cells that had been stored at ‐80 C for 1.8 years and longer and washed by the Huggins procedure showed intravascular destruction of the compatible nonviable red blood cells. Huggins‐preserved red blood cells with EDTA that had been stored at ‐80 C up to 1.6 years showed, following washing with an electrolyte solution in the ADL bowl, a somewhat better 24‐hour ADA survival, better recovery of the preserved red blood cells, lower supernatant hemoglobin concentrations, and higher intracellular potassium levels on the day of washing and resuspension. These findings suggest that Hugginspreserved red blood cells following storage at ‐80 C for one and one half years or more should not be washed by the Huggins dilution/agglomeration procedure.     

5-day storage of single-donor platelets obtained using a blood cell separator

Platelets were collected from normal donors via a blood cell separator (Fenwal CS-3000). Platelets were stored initially in two separate 1000-ml bags (average count per bag, 2.3 +/- 0.5 x 10(11)) in 100 ml of autologous plasma for 5 days. Little change in platelet count was noted after 5 days of storage; however, the white cell count fell from 5.1 +/- 1.7 x 10(9) at Time 0 to 3.4 +/- 2.3 x 10(9) per l at Day five. The initial lactate values were 32 +/- 11 mg per dl and rose to 165 +/- 28 mg per/dl by 5 days. Platelet aggregation was impaired both by the collection procedure and during storage: whereas the response to ADP of the donors' platelets before the procedure was 100 percent, samples taken from the product immediately after collection had only a 45 percent response, which fell to 12 percent by Day 5. Aggregation using epinephrine was similarly affected, with a 75 percent response after collection and 0 percent response by Day 5. The plasma beta-thromboglobulin (beta-TG) level was high, both after collection (5.0 micrograms/ml at Time 0) and after storage (11.0 micrograms/ml), indicating a considerable effect of collection on platelet alpha granule release. In vivo recovery of these platelets was very good at 67 +/- 6 percent, with an average survival of 7.3 +/- 1.4 days (multiple hit; n = 4).(ABSTRACT TRUNCATED AT 250 WORDS)     

Albumin and Hydroxy‐Ethyl Starch in the Cryopreservation of Red Cells—an In Vitro Study

The usefulness of a fully dialyzed albumin in ACD‐saline containing hyroxyethyl starch (HES) for cryoprotection of red blood cells has been investigated. In vitro damage was as assessed by the amount of hemolysis in the supernatant plasma, saline stability, and autohemolysis at 30 C after resuspension in fresh ACD plasma. Freeze‐thawing hemolysis was reduced to an average of 54 per cent of that of the control when the cells were processed in 14.1 g 100 ml albumin containing 11.7 g 100 ml HES. Higher concentrations of albumin reduced this difference of 46 per cent to 20 per cent. The autohemolysis test gave the best result, when 21.7 g/100 ml albumin was used as HES diluent.
Additionally the effect of freeze‐thawing on the cellular levels of ATP and 2,3‐DPG was investigated. The ATP levels in the albumin‐HES processed cells fell to 94 per cent and that of the ACD plasma‐HES cells to 85 per cent of the respective starting values. 2,3‐DPG in the corresponding samples was reduced to 98 and 96 per cent of the initial levels. The differences between cells processed in both media were statistically not significant. Cell membrane deformability was tested by cell filtration. Cells processed in albumin‐HES had a shorter filtration time than those frozen in ACD plasma‐HES and this difference was statistically significant.     

Platelet storage. Effects of leachable materials on morphology and function

A polyolefin plastic (PL 732) bag formulated without liquid plasticizer allows storage of platelets for 5 and, now, up to 7 days. In order to assess the leaching of compounds from this new plastic, extracts of the supernatant from platelet concentrates stored in these bags were analyzed by high-performance liquid chromatography, mass spectrometry, and gas-liquid chromatography. A leachable material was detected and identified as di(2-ethylhexyl) phthalate (DEHP). During the sterilization process, migration of the DEHP occurs from the polyvinylchloride (PVC) bags into the PL 732 plastic bag. The level of DEHP was 12-fold less in the extracts of PC supernatant stored in the PL 732 bag than those in the polyvinyl chloride (PL 146) plastic bags which were used previously for platelet storage. Platelets stored in low DEHP concentrations in the PL 732 bags were composed of 10 to 35 percent of unclassifiable shapes. These shape changes were not observed in higher concentrations of plasticizer, although the morphology scores decreased during storage in PL 146 as well. This effect on morphology was not related directly to the dose of DEHP. When platelet membranes were isolated from platelets stored in the presence of radiolabeled DEHP, the amount of bound 14C-DEHP was found to be directly proportional to the concentration of DEHP in the plasma supernatant. However, while there was a linear relationship between the protein concentration in the membrane fraction and the amount of bound DEHP, no specific DEHP binding site could be identified by electrophoresis of the solubilized platelet membranes.     

Storage of single donor platelet concentrates: Paired comparison of storage as single or double concentrates

Modern cell separators allow the collection of two plateletpheresis concentrates (PCs) at one session. This study evaluates the quality of PCs stored as double concentrates in standard storage containers of two manufacturers. We collected 20 PCs that contained 4.5 × 10¹¹ platelets in 375 ml plasma (10 using the COBE Spectra and 10 using the Fresenius AS.TEC 204 with 500 ml bags) that were split into one unit of 3.0 × 10¹¹ platelets in 250 ml (3.0‐PC) and one of 1.5 × 10¹¹ platelets in 125 ml (1.5‐PC). Storage of one 3.0‐PC per bag of a two‐bag system corresponded to storage conditions for double PCs and storage of one 1.5‐PC per bag to storage conditions of single PCs. Cell counts, blood gas analysis, glucose and lactate levels, platelet aggregation, and activation and plasma levels of β‐ thromboglobulin (β‐TG) and complement factor 3a (C3a) were measured before storage and again on days 3 and 5. COBE 3.0‐PCs demonstrated less pH rise, lactate production, CD 62P expression and β‐TG plasma levels, and better aggregability after storage than COBE 1.5‐PCs. Fresenius 1.5‐PCs had similar platelet quality to COBE 3.0‐PCs. Fresenius 3.0‐PCs showed a fall of pH (day 5: 6.22 ± 0.56), the highest amount of anaerobic glycolysis compared to all other storage conditions investigated, high CD 62P‐ expression and β‐TG plasma levels, and impaired aggregability on days 3 and 5. The highest C3a levels were found in COBE 1.5‐PCs. 3.0 × 10¹¹ platelets in 250 ml plasma should be stored either in one bag of the COBE system or in two 500 ml bags of the Fresenius system. The COBE two‐bag system allows the storage of two PCs without loss of platelet quality. Two PCs should not be stored in the Fresenius C4L 500 ml storage containers. J. Clin. Apheresis. 16:148‐154, 2000. © 2001 Wiley‐Liss, Inc.     

Effects of the new glycopeptide antibiotic teicoplanin on platelet function and blood coagulation.

Teicoplanin, a new glycopeptide antibiotic, is structurally related to ristocetin, an antibiotic known to induce human platelet agglutination and, thus, thrombocytopenia and thromboembolic side effects. The aim of this study was to evaluate the effects of teicoplanin on platelet function in vitro and ex vivo and on blood coagulation ex vivo. In the in vitro studies, spontaneous platelet aggregation; platelet aggregation induced by ADP, collagen, and ristocetin; and the release of beta-thromboglobulin from platelets were assessed. Platelets from healthy subjects were incubated with teicoplanin at final concentrations of 100, 1,500, 5,000, and 10,000 micrograms/ml. The maximal achievable concentration with therapeutic doses is 100 micrograms/ml. When compared with saline, teicoplanin at concentrations of 100 and 1,500 micrograms/ml had no effect on platelet function, but at concentrations of 5,000 and 10,000 micrograms/ml, it induced greater spontaneous platelet aggregation (P less than 0.01) and inhibited platelet aggregation induced by ADP, collagen, and ristocetin (P less than 0.01). Teicoplanin at concentrations of 100, 1,500, and 5,000 micrograms/ml did not induce the release of beta-thromboglobulin, in contrast to teicoplanin at a concentration of 10,000 micrograms/ml and ristocetin at a concentration of 1.5 mg/ml (P less than 0.01). In the ex vivo studies, platelet count, bleeding time, plasma beta-thromboglobulin, platelet aggregation induced by ADP, ristocetin, and epinephrine, activated partial thromboplastin time, prothrombin time, thrombin clotting time, and serum fibrinogen degradation products were evaluated at days 0, 3, and 6 and at 72 h after the end of therapy. All subjects completed the study without evidence of side effects. When compared with the pretreatment values, none of the values from these assays showed a significant change at any time during and after treatment. We concluded that platelet function and blood coagulation are not affected by therapeutic concentrations of teicoplanin and that in vitro platelet function is affected only by concentrations of teicoplanin far in excess of those that are clinically achievable.     

以海藻糖为添加剂冷藏保存血小板悬液的研究

本研究探讨以海藻糖(trehalose)为添加剂的血小板悬液冷藏保存方法。采用核素标记法检测血小板生存时间,用比浊法测定血小板聚集率,诱导剂为终浓度11.2μmol/L的ADP。采集兔心脏血,按常规方法制备浓缩血小板悬液(PCs),在悬液中加入50mg/ml的海藻糖,37℃水浴4小时后,放于4-8℃冰箱保存,冷藏12天后,测定血小板聚集功能和输入自身体内后的生存时间。结果表明:常温和冷藏储存24小时后的PC血小板聚集率分别为(75.3±9.8)%和(80.5±12.5)%;输入兔体内24、48和72小时时的血小板存活率分别为(78.1±7.9)%、(65.4±6.7)%、(57.5±7.2)%和(5.1±2.5)%、(2.8±2.0)%、(0.9±0.8)%。加入海藻糖的PC冷藏保存12天后,血小板聚集率为(77.8±9.5)%;输入体内24、48和72小时时的血小板存活率分别为(75.7±11.0)%、(67.0±8.5)%、(56.8±8.0)%,与常温保存24小时对照相比,两者相近,P值均>0.05。结论:海藻糖能保护冷藏储存的兔血小板,延长冷藏血小板在体内的生存时间,经海藻糖冷藏储存的兔血小板功能完好。     

Measurement of Erythrocyte Survival during Open‐heart Surgery

A method of estimating erythrocyte survival during open‐heart surgery is presented. Two erythrocyte populations were transfused simultaneously into the extracorporeal circulation and were compared by measuring the survival of one population with ⁵¹Cr labeling and the other by automated differential agglutination. The difference between the percentage survivals of two erythrocyte populations was calculated. When the survival of a single erythrocyte population was measured simultaneously by chromium labeling and by automated differential agglutination, evidence for elution of chromium from the labeled red blood cells during the operative procedure was not found. A significant increase in the rate of erythrocyte destruction occurred following transfusion of red blood cells that had been stored at 4 C for longer than one week. The destroyed red blood cells apparently represented those irreversibly damaged during storage at 4 C.     

A new polyvinylchloride blood bag plasticized with less-leachable phthalate ester analogue, di-n-decyl phthalate, for storage of platelets

To compare changes in platelets stored in the new di-n-decyl phthalate (DnDP)-plasticized polyvinyl chloride (PVC) bag with those in a di-(2-ethylhexyl) phthalate (DEHP)-plasticized PVC bag, single-donor apheresis platelet concentrates (PCs), 133 +/- 11 x 10(7) platelets per ml (n = 7), were stored with 94 +/- 3 ml of plasma in a new 1-liter bag with a surface area of 44 +/- 7.1 cm2 per 10(10) platelets. Oxygen and carbon dioxide gas diffusion properties of PVC-DnDP films were respectively, 1.6 and 2 times those of standard PVC-DEHP films. The amounts of DnDP leaked into the plasma of PCs were low at 0.58 +/- 0.06 mg per bag after 5-day storage, which is about one-eightieth the amount of DEHP leaked. The pH of PCs in PVC-DnDP bags amounted to 6.99 +/- 0.03 after 5-day storage, with glycolysis accelerated somewhat in the new bags. However, the platelet oxygen consumption was no different from that in the PVC-DEHP bags. Platelet aggregation and responses to hypotonic shock were significantly better in the new bags at the end of storage. Shape changes of platelets into spherical forms with dendrites were more frequently observed in PVC-DnDP bags than in PVC-DEHP bags. The study indicated that platelets stored in the new DnDP-plasticized PVC bags have retained aggregation and responses to hypotonic shock more than platelets in the PVC-DEHP bags, but spherical forms and anaerobic metabolism increased in the new bags.     

Stability of platelet surface antigens during storage

We measured changes in A, B, 2H, PlA1, and HLA Class I antigens on human platelets stored as routine platelet concentrates (PCs) in 50 to 60 ml of citrate-phosphate-dextrose-adenine (CPDA-1) plasma in polyolefin (PL 732) bags at 22 degrees C with continuous cartwheel rotation. Samples were obtained at 1, 3, 5, and 10 days of storage; incubated with human IgG anti-A, -B, -HLA and -PlA1; incubated with mouse monoclonal 125I-labeled anti-human IgG; centrifuged through phthalate ester oils; and assayed in a gamma scintillation counter. Additionally, group O platelets were analyzed using 125I-labeled IgM mouse monoclonal anti-Type 2H. Mean values for molecules of Ig bound per platelet showed that platelet surface antigens A, B, 2H, PlA1, and HLA Class I showed no significant change during 10-day storage as routine PCs in CPD-A1 in PL 732 bags. Identical radioassays were performed with platelets incubated at 22 degrees C in plastic test tubes for 24 hours in homologous plasma from donors negative for the respective antigens and in a variety of artificial media with albumin and lipids. No significant changes occurred in any of the surface antigens, except for the loss of approximately 50 percent of the blood group A antigen from platelets stored in O plasma or in albumin media. These data indicate that HLA, PlA1, and type 2H structures do not readily dissociate from the platelet membrane during storage, while some blood group A antigens, presumably acquired passively from the plasma, will elute from the platelet under certain conditions. Routine storage conditions are unlikely to alter the immunogenicity of platelets due to a loss of antigen expression.     

Seven-day storage of apheresis platelets: report of an in vitro study

BACKGROUND: The objective of this study was to determine the allowable platelet content limits for apheresis platelets stored for 7 days in a platelet storage bag (COBE ELP, Gambro BCT). METHODS: Apheresis platelets under controlled concentration and volume per bag were stored in plasma up to 8 days at 22 degrees C with horizontal agitation. Routinely evaluated in vitro platelet parameters were followed. Oxygen consumption was directly measured with a Clark-type electrode. All components were cultured in aerobic medium on Day 7. RESULTS: Twenty-four components were evaluated in storage configurations (median [range], 340 [110-402] mL, 1.32 [0.99-2.45] x 10(6) platelets/microL, and 4.8 [1.4-5.9] x 10(11) platelets/bag). No bacterial contamination was detected. One component had a pH value at 22 degrees C of below 6.0 before Day 5 with attendant loss of all other in vitro function measures. The pH value at 22 degrees C was maintained above 6.2 for the remaining 23 components. A pH value of greater than 7.4 was observed at some point in storage for 13 of 23 units, although platelet function or activation was not adversely affected. Aerobic metabolic function was maintained over 7 days with O2 consumption of 321 micromol per hour per 10(12) platelets on Day 7. CONCLUSION: Although a continuing decline of platelet in vitro characteristics can be observed for storage beyond 5 days, apheresis platelets in plasma stored 100 to 400 mL per bag, 1.0 x 10(6) to 2.5 x 10(6) platelets per microL, and a maximum of 5.1 x 10(11) platelets per bag maintained in vitro platelet characteristics over 7 days of storage.     

Platelet membrane glycoprotein changes during the preparation and storage of platelet concentrates

Previous studies of platelet membrane glycoproteins during blood bank storage have reported conflicting results. This study assessed two major plasma membrane glycoproteins (GP Ib and GP IIb), an alpha-granule membrane protein (GMP-140), and the concentration of platelet membrane microparticles in cell-free plasma during routine hospital blood bank platelet storage. 125I-monoclonal antibody binding was used to measure membrane glycoproteins on the surface of intact platelets and to measure the concentration of membrane microparticles in cell-free plasma. Platelet concentrates were stored at room temperature in polyolefin bags for 7 days. In this blood bank, two types of rotators are routinely used for platelet concentrate storage: a 2-rpm circular tumbler rotator and a 6-rpm elliptical rotator. Different results were obtained with the rotators. With the tumbler rotator, there was no loss of platelets and antibody binding to GP Ib remained normal. With the elliptical rotator, one third of platelets were lost into clumps during storage, and a 50 percent decrease of antibody binding to GP Ib occurred in the remaining single platelets. There was no loss of antibody binding to GP IIb with either rotator. Antibody binding to GMP-140 increased equally in both rotators indicating that the remaining single platelets had secreted about 16 percent of their alpha-granule contents. The plasma concentration of platelet membrane microparticles was greater in the bags stored in the elliptical rotator. These results indicate that it is possible to maintain the normal concentration of platelet membrane glycoproteins Ib and IIb during 7 days of room-temperature blood bank storage.(ABSTRACT TRUNCATED AT 250 WORDS)     

Hyperbaric treatment of platelets is comparable to cold storage alone over 14 days

Background

Platelets stored at room temperature (22–24°C) for transfusion purposes have a shelf life of 5–7 days, or 72 h when stored refrigerated (1–6°C). The limited shelf life of platelet products severely compromises platelet inventory. We hypothesized that cold storage of platelets in 100% plasma using xenon gas under high pressure would extend shelf life to 14 days.

Study Design and Methods

Double apheresis platelet units were collected and split equally between two bags. One unit was placed in a hyperbaric chamber, pressurized to 4 bars with a xenon/oxygen gas mixture, and placed in a refrigerator for 14 days (Xe). The remaining unit was aliquoted into mini-bags (10 ml) for storage at room temperature (RTP) or in cold (CSP). Samples were assayed on days 5 (RTP) or 14 (Xe and CSP) for count, metabolism, clot strength, platelet aggregation, and activation markers.

Results

The platelet count in Xe samples was lower than that of RTP but significantly higher than CSP. Despite similar levels of glucose and lactate, the pH of Xe samples was significantly lower than CSP. Glycoprotein expression was better preserved by Xe storage compared to CSP, but no differences in activation were observed. Thromboelastography and aggregometry results were comparable between all groups.

Discussion

Cold storage of platelets in plasma with hyperbaric xenon provides no significant improvement in platelet function over cold storage alone. The use of a hyperbaric chamber and the slow off-gassing of Xe-stored units complicate platelet storage and delivery logistics.     

The accumulation of mono-2-ethylhexylphthalate (MEHP) during storage of whole blood and plasma

The accumulation of the plasticizer di-2-ethylhexylphthalate (DEHP) in blood and blood components has been of considerable concern for some time. We have followed the accumulation of DEHP and one of its major metabolities, mono-2-ethylhexylphthalate (MEHP) during storage of whole blood, platelet-rich plasma, platelet concentrates, and platelet-poor plasma for periods ranging from 72 hours to four weeks. Both phthalates showed a progressive increase in concentration with time. While the levels of DEHP were much greater than those of MEHP, there was nonetheless a significant and continual increase in MEHP in all preparations. The highest concentrations of both DEHP and MEHP were found in the platelet-poor plasma, indicating that platelets do not have a major role in the accumulation of the phthalates in blood. The accumulation of MEHP was shown to be a direct result of the metabolism of DEHP by plasma protein(s) rather than leaching from the blood bag.