Solid-phase Red Cell Adherence Assay Research Articles

Comparison of the solid-phase red cell adherence assay and tube method for detection and identification of red blood cell antibodies.

Identifying antibodies to red blood cell antigens is one of transfusion medicine's critical responsibilities. The International Society of Blood Transfusion recognizes 354 red blood cell antigens. Accurate identification of clinically significant alloantibodies is imperative for preventing hemolytic transfusion reactions and hemolytic disease of the fetus and newborn. We compared the performance of the tube (polyethylene glycol-indirect antiglobulin test [PEG-IAT]) and solid-phase red cell adherence assay techniques. We performed a retrospective study on all antibody screens performed between 2007 and 2021 at Stanford Transfusion Services. Initially, 631,535 antibody screens were performed using a solid-phase technique. Subsequent antibody identifications were performed using a combination of tube testing and solid-phase techniques. Antibody screening resulted in 28,316 (4.5%) positive samples. Antibody identification performed on both platforms identified 50 discordant samples. The anti-E antibody had the lowest sensitivity (98.99%) in the automated solid-phase technique, while anti-Jkb had the lowest sensitivity (98.78%) with the PEG-IAT method. To our knowledge, this is the first robust, 15-year study comparing methodologic sensitivity to detect clinically significant alloantibodies. The incidence of discordant results between PEG-IAT and the solid-phase technique was low. Among discordant samples, anti-Jka was commonly detected using the solid-phase method but not with the PEG-IAT. In contrast, anti-E was commonly detected by PEG-IAT but not by the solid-phase method.

The impact of an antibody investigation algorithm emphasizing specificity on reducing potential false-positive warm autoantibody detection at a Canadian tertiary care centre.

To reduce potential false-positive warm autoantibody (WAA) by solid-phase red cell adherence assay (SPRCA), our centre implemented a new antibody investigation algorithm (AIA) by classifying cases with panreactive SPRCA but negative saline-indirect antiglobulin test as 'antibody of undetermined significance' (AUS) after excluding clinically significant antibodies. We assessed the effects of the new AIA and subsequent alloantibody formation in patients with AUS. Samples from patients with positive SPRCA screens between 1 September 2017 and 31 August 2021 were selected for the study. Frequencies of antibodies classified by the old and new AIAs were compared using Fisher's exact test. Patient demographics, transfusion history and antibody formation in cases of AUS were collected. A significant reduction in potential WAA frequencies from 127/1167 (11%) to 53/854 (6%) was observed (p < 0.001) when compared between the old and new AIAs among 2021 positive SPRCA antibody screens. While no patients with AUS later transitioned to potential WAA using the new AIA, four patients developed alloantibodies, including anti-E, anti-C, both anti-C and anti-E, and anti-Wra . A significant reduction in the frequencies of potential false-positive WAA detection at our centre was observed after implementing the new AIA, leading to less resource and phenotypically matched red blood cell (RBC) use. Some patients still developed subsequent RBC alloimmunization, so clinically relevant alloantibodies should be carefully excluded before determining AUS, taking forming or evanescent antibodies into consideration.

Does decreasing the incubation period used in the antibody screen affect its sensitivity?

Pre-transfusion testing (PTT) encompasses a set of mandatory laboratory tests performed before red blood cell transfusion. The antibody screen, one component of PTT, commonly includes a 10-20 min incubation. The primary aim of this study was to determine if this period can be reduced when using current immunohematology methodologies. Antibody screens were performed on reagent samples using Glass or Gel-based column agglutination technologies (CAT) and a solid phase red cell adherence (SPRCA) assay, with incubation periods of 1, 5, 10 and 15 min, and 20 min (SPRCA assay only). For each method, the shortest period producing a minimum of a 1+ reaction with all reagent samples was considered optimal. The sensitivity of each assay using the optimal period was calculated after performing antibody screens on 100 patient samples. It was demonstrated that the incubation period in the SPRCA and Glass CAT systems can be reduced to 5 and 10 min, respectively, while achieving high assay sensitivity (98.9% in both). The incubation period in the Gel CAT system cannot be reduced from 15 min. Significant association between titre and reaction strength was observed for all three screening methods (p < 0.001 for both CAT methods, p = 0.041 for SPRCA). This study demonstrates that the incubation period used in the antibody screen can be reduced when using systems employing the Glass CAT and SPRCA methods, without affecting assay sensitivity. If confirmed, it could result in faster completion of PTT.

Therapeutic Efficacy of Platelet Transfusion and Analysis of Influencing Factors in 364 patients

Introduction: The aims of this study were to observe the therapeutic effect of platelet (PLT) transfusion and to analyze influencing factors for the sake of providing useful clues for improving the efficacy of PLT transfusion. Methods: Included in this study were patients who received PLT transfusion in the affiliated hospital of Nantong University. Patients’ sex, age, height, weight, PLT transfusion status, and 20–24-h PLT count before and after PLT transfusion were collected to calculate the PLT corrected count increment values before and after PLT transfusion. Solid-phase red cell adherence assay was used to determine PLT antibody. Statistical analysis was performed using SPSS25.0 Software. Results: A total of 364 patients received 1,060 PLT transfusions, including 728 successful transfusions and 332 unsuccessful transfusions. When the patients were grouped according to different etiologies, significant differences in PLT transfusion effectiveness were observed between these groups (χ² = 15.070, p < 0.05). Grouping of the 364 patients according to sex, blood type, and PLT transfusion frequency showed no significant difference in PLT transfusion refractoriness (PTR) between different age-groups and sexes (p > 0.05). With the number of PLT transfusions increasing, PTR increased gradually. PLT antibodies were detected of 364 patients, 67 of them were positive. Among them, 63 cases (94.02%) were positive for HLA class I antibody. Conclusion: To reduce PTR, multiple factors should be considered comprehensively when PLT transfusion therapy is to be implemented in clinical practice. PLT antibody is the main immune factor causing PTR.

Evaluation of influence of IL-6 C-572G gene polymorphism and clinical factors on positive platelet antibody test

Background: Interleukin-6 (IL-6) promotes antibody production. The objective of this study was to investigate whether IL-6 C-572G single nucleotide polymorphisms (SNP) and clinical factors are associated with positive platelet antibody test. Materials and methods: Thirty platelet recipients with platelet antibodies (responders) and 20 platelet recipients without platelet antibodies (non-responders) were randomly selected. The -572 C&gt;G (rs 1800796) SNPs in the promoter region of IL-6 gene were genotyped by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) method. Solid phase red cell adherence assay (SPRCA) was used for platelet antibody detection. Results: Age, sex, percentage patients with benign diseases, and percentage of patients with homozygotes for the C allele at position -572 of the IL-6 gene were similar between responders and non-responders. Although the amounts of platelets pheresis transfused to patients with hematologic diseases were higher than those of non-hematologic diseases (47.2 ± 54.2 vs. 17.4 ± 13.8 units, p = 0.019), detection rate of platelet antibodies was lower in patients with hematologic diseases than that in patients with non-hematologic diseases (42.3% vs. 79.2%, p = 0.01). Conclusion: There was no association between IL-6 C-572G gene polymorphism and positive reactivity in solid phase platelet antibody detection method in platelet recipients.

Correlation of platelet crossmatch results by Solid Phase Red Cell Adherence Assay (SPRCA) with post-transfusion platelet count increment in adult hemato-oncology patients of a tertiary care oncology centre in India

AimsTo assess platelet crossmatch result by SPRCA and find its correlation with post-transfusion platelet count increment among adult hemato-oncology patients. MethodsA prospective observational pilot study of 50 adult hematologic malignancy patients previously transfused, but not already known to be transfusion-refractory and without any nonimmune causes for inadequate response to platelet transfusion were included after obtaining informed consent. They were transfused one unit of ABO identical single donor platelet. Ten minutes to 1 -h post-transfusion CCI was calculated.CCI ≥ 7500 was considered as adequate response. Post-transfusion crossmatching by SPRCA was performed by using preserved platelet samples from donor units with the serum of the respective patient. Statistical analysis of the correlation between platelet crossmatch results and CCI was done. ResultsOut of 50 crossmatches, 78% (39/50) showed compatible and 22% (11/50) showed incompatible results. Among 39 compatible results, 87.2% (34/39) showed adequate CCI and 12.8% (5/39) showed inadequate CCI. Among 11 incompatible results, 18.2% had adequate CCI and 81.8% had inadequate CCI. The difference between the response in terms of CCI to compatible and incompatible crossmatches was found to be statistically significant (p < 0.05). Other variables like age, sex, number of previous transfusions and underlying clinical condition of the patient were not found to have any effect on the compatibility of crossmatch. ConclusionsTransfusion of crossmatched platelets to non-refractory, multiply transfused hematological malignancy patients without serious illness might provide a small benefit over transfusing randomly selected platelets, though these data must be confirmed with a larger sample size.

Efficacy of cross-match compatible platelets in multi transfused haemato-oncology patients refractory to platelet transfusion

BackgroundPlatelet refractoriness, which leads to platelet transfusion failure resulting in significant morbidity and long hospital stay, is routinely not investigated. AimsTo determine the efficacy of cross-match compatible platelets in multi-transfused alloimmunized hemato-oncological patients refractory to platelet transfusion. Materials and method149 ABO compatible single donor apheresis platelet transfusions given to 38 alloimmunized refractory patients. Corrected Count Increment (CCI) <5000 (1 h) was taken to define refractoriness. Solid-phase red cell adherence assay was used to determine the alloimmunization status and platelet cross-matching. Post Transfusion Platelet Increment, CCI and the Percentage Platelet Recovery were used to monitor the effectiveness of platelet transfusion. ANOVA test followed by Post hoc test Tukey HSD used to compare group means and classified into three groups depending upon the cross-matching and compatibility status. Categorical data was analysed for various outcomes using Pearson's chi square test or Fischer exact test. ResultPatients showed statistically significant recovery in terms of PPI, CCI and PPR at 1 h post SDAP transfusions when they received cross-matched compatible platelets. The one-hour CCI was significantly higher for cross-match-compatible platelets (19173 ± 2692) than for incompatible (5888 ± 1526) and for uncross-matched (8140 ± 1480). Forty four (97.8%) of 45 cross-matched compatible platelet transfusion episodes showed a satisfactory response in terms of PPI and CCI values as compared to 50 % and 53.9% in uncross-matched group respectively (p < 0.0001). ConclusionPlatelet cross-matching is an effective intervention in the management of multi-transfused alloimmunized Haemato-oncological patients, refractory to platelet transfusion.

Red Cell Alloantibody Screening: Comparative Analysis of Three Different Technologies

Background: The detection of irregular antibody is a critical issue in the management of red blood cell transfusion according to the Type & Screen (T&S) practice. In order to implement the T&S procedure at our blood bank, we compared three different automated analyzers based on column agglutination technique (CAT) or solid phase red cell adherence assay (SPACA) methods. Methods: Pre-transfusion antibody screening was performed in 986 patients candidate to elective surgery at low risk for red blood cell transfusion. We tested the following kits: the three-cell panel micro-CAT system ID-DiaCell I-II-III (DiaMed), the four-cell panel solid-phase system Capture-R Ready Screen-4 (Immucor), and the four-cell panel micro-CAT system Serascan Diana-4 (Grifols). Positive results were further investigated using corresponding identification panels, and discrepant results were investigated with all the antibody identification systems. Results: Among 986 samples, we observed 967 concordant negative results (98.1%), 8 concordant positive results (0.8% of cases), and 11 discrepant results (1.1%). Among discrepant samples, an alloantibody could been identified in two patents (anti-M, detected by Serascan Diana-4 and ID-DiaCell I, II, III; anti-Kp^a, detected by Capture-R Ready Screen-4 and Serascan Diana-4). Conclusion: Among the evaluated technologies, the four-cell panel micro-CAT system displayed the highest sensitivity and specificity with an optimal negative predictive value. These features might be relevant to the routine implementation of the T&S transfusion strategy.

Antibody identification using both automated solid‐phase red cell adherence assay and a tube polyethylene glycol antiglobulin method

Because antibody identification is labor-intensive, facilities with high volume and/or marginal technical support could benefit from partial automation. After a validation study of automated solid-phase red cell (RBC) adherence assay (SPRCA; Galileo, Immucor) compared to tube polyethylene glycol antiglobulin antibody identification method (t-PEG), we evaluated Galileo followed by select RBC panels by t-PEG. Of 298 consecutive samples in which antibody identifications were performed in a 2-month period, 160 samples were examined by both Galileo and t-PEG. There were concordant results between Galileo and t-PEG in 120 of 160 (75%) samples including cases with identical alloantibody identification (n = 99), panagglutinin (n = 9), and negative results (n = 12). Of the samples in which alloantibodies were identified, 99 of 108 (91.7%) were identical. In 9 samples with discrepant antibody identifications, 2 samples showed alloantibody specificity by Galileo (possible anti-K and anti-Jk(b)) but were negative by t-PEG. These antibodies were identifiable by t-PEG in subsequent samples. One sample showed anti-E by Galileo, while t-PEG revealed anti-Fy(a) and -E. Five samples showed alloantibody specificity by t-PEG and nonspecific reactivity or panagglutinin by Galileo. These included samples with anti-C (n = 2), anti-E (n = 2), and anti-Fy(a) (n = 1). One sample showed anti-E by t-PEG but was negative by Galileo. Galileo found a panagglutinin in 23 samples and nonspecific reactivity in 22 samples, whereas t-PEG found a panagglutinin in 12 samples but no nonspecific reactivity. Automated Galileo solid-phase red cell adherence assay can be a useful adjunct for antibody identification, although it detects more nonspecific reactivity than does t-PEG.

Screening for Platelet Antibodies in Adult Idiopathic Thrombocytopenic Purpura: A Comparative Study Using Solid Phase Red Cell Adherence Assay and Flow Cytometry

Idiopathic thrombocytopenic purpura (ITP) is an autoimmune disorder caused by antiplatelet autoantibodies. In this study, we compared 2 methods for screening serum platelet antibodies in patients with ITP. A total of 44 adult patients were clinically classified with ITP. We used 2 indirect tests to detect human leukocyte antigen antibodies and/or platelet-specific antibodies in their sera. In method I, we used solid phase red cell adherence (SPRCA) assay. In method II, by flow cytometry, platelets from plateletpheresis components were used as target cells, and fluorescein isothiocyanate-conjugated sheep anti-human IgG Fc was used as the staining reagent. Positive results were defined as any test with the percentage of fluorescence exceeding the reference range by 3% or more in method II. Direct tests detecting platelet-associated IgG on platelets of patients with ITP were done by flow cytometry. Serum specimens from 44 adult patients with ITP (28 female, 16 male) were tested. SPRCA assay could only detect platelet antibodies in 22 patients (50%). By method II, 31 serum specimens (70.5%) yielded positive results. There was a difference between the results of the SPRCA test and method II, with a high degree of significance (p < 0.001) by the McNemar test. No significant difference in platelet counts was observed for patients with and without discernible platelet antibodies by SPRCA assay (p = 0.90). The direct test was positive in 12 patients (66.7%) out of 18 ITP patients tested. Flow cytometry is more sensitive than SPRCA assay for detecting platelet antibodies. Detection of platelet antibodies is useful in explaining the immune mechanism and platelet transfusion refractoriness in ITP.

Optimizing pretransfusion antibody detection and identification:a parallel, blinded comparison of tube PEG,solid‐phase, and automated methods

The ideal pretransfusion testing strategy identifies maximal significant antibodies at minimal cost. Objectives of this study were to compare the characteristics of three testing methods and determine their optimal incorporation into the following generic testing sequence: 1) screen, for antibodies 2) if results are positive, use primary identification method, 3) if results are inconclusive, use secondary identification method. A total of 2000 consecutive, unselected, coded specimens were tested with three screening methods-PEG IAT, manual and automated solid phase red cell adherence assay (SPRCA). Of 202 positive results, 187 were of sufficient volume and were tested with both PEG and manual SPRCA identification panels, yielding 82 with significant antibodies, plus one that was negative by both methods found on retrospective review of nonstudy results. Calculations were made on the 1985 volume-sufficient specimens, simulating the possible testing permutations. Manual SPRCA was the most sensitive antibody screen (67/83 = 81%) and the least specific (1840/1902 = 97%); automated SPRCA was the least sensitive (54/83 = 65%) and most specific (1883/1902 = 99%); and PEG was intermediate in both sensitivity (64/83 = 77%) and specificity (1860/1902 = 98%). Of the identification panels, manual SPRCA identified more antibodies than PEG (67 versus 66) but had more inconclusive results (41 versus 20). Of overall strategies, manual SPRCA screening with either sequence of identification methods identified the most antibodies (66). The combination of PEG screen, PEG identification, and manual SPRCA identification identified slightly fewer antibodies (63) but had the lowest reagent cost, total (reagent plus labor) cost, and cost per antibody identified. The sequence of automated SPRCA screening with manual SPRCA identification, and PEG identification had the lowest hands-on time. The most cost-effective pretransfusion strategy is PEG screen with PEG identification, plus manual SPRCA identification when PEG identification is inconclusive.

Confirmation of positive antibody screens by solid-phase red cell adherence assay using a tube technique method with polyethylene glycol enhancement

Abstract Our blood bank routinely screens donors for antibodies using a solid-phase red cell adherence (SPRCA) assay. Positive results are then confirmed using a tube technique with polyethylene glycol (PEG) enhancement due to reported higher specificity than with SPRCA. Over a 5-month period, 49,084 donor serum or plasma samples were tested using the SPRCA assay. Further identification of positive samples was performed using a PEG enhancement method. Testing was performed with strict adherence to the manufacturers’ inserts. Of 49,084 samples, 313 (0.64%) were positive by the SPRCA assay. Of these, 99 (31.6%) samples remained positive when tested with PEG enhancement. The remaining 214 (68.4%) were negative, giving specificity for the SPRCA assay of 99.6 percent (48,985/ 49,199). We report a high specificity for antibody screening using the SPRCA assay. However, it is cost effective to perform a confirmatory tube test with PEG enhancement because 214 SPRCA assay samples were interpreted as having a negative antibody screen, thus allowing the release of valuable blood components for transfusion. Immunohematology 2001;17:14–16.

The Diego blood group system-an update

Abstract Anti-Jka was detected by solid-phase red cell adherence(SPRCA) anti-body detection and identification tests in the plasma of a 9-month-old female intant during a roatine presurgical evaluation. the pation and her nonidentical twin sister who also had anti-Jka in her plasma, were products at an uncomplicated in vitro fertilization, full -term preganancy, and vaginal delivery Neither twin had been tranfered recently infected. or treated with medication. their mother had no prior pregnancies or transfusions. Red blood cells (RBCs) from the patient and her sister typed as Jk(a-b+) by direct hemagghutination and this phenotype was confirmed by negative adsorption and elution studies. Both infants plasma samples were strongly reactive with 20 examples of Jk(a+) RBCs and nonreactive with 20 examples of Jk(a-) RBCs by SPRCA assays. Anti-Jka was not detected in either twins plasma by Indirect antiglobulin tests by tube method in lowionie-strength saline solution or polyethylene glycol, or with ficin- or papain-treated RBCs. Monocyte monolayer assays using Jk(a+) RBCs sensitized by either twins’ serum were nonreactive (0%). RBCs from both parents typed as Jk(a+b+). Both parents’ antibody detection test results by SPRCA assay were negative. The absence of a history of exposure to allogeneic RBCs or possible passive transfer of maternal or other alloantibody classifies these antibodies as natually-occurring anti-Jka. Immunohemalology 1999;15: 159-162.

Detection of drug-dependent, platelet-reactive antibodies by solid-phase red cell adherence assays.

We developed a simple modification of the solid-phase red cell adherence (SPRCA) assay system that can be used to identify drug-dependent platelet antibodies (DDPAs) reactive by either the hapten or immune complex reaction mechanisms. Between January 1994 and August 1996 we tested sera from 173 patients [123 (71%) with unexplained thrombocytopenia and 50 (29%) because of poor responses to platelet transfusions not explicable by alloimmunization or the clinical situation] for DDPAs possibly associated with the receipt of 61 different drugs. We correlated positive results with patients' clinical courses. DDPAs were identified in samples from 138 (80%) of the patients tested. Antibodies reactive only by the hapten mechanism were identified in 51 (37%) of those sera exhibiting positive reactions. The clinical courses of 108 (78%) patients were evaluable. Discontinuation of the implicated drug(s) resulted in prompt (<5 d) resolution of the thrombocytopenia or improvement in response to transfusion in all of these patients. In four cases thrombocytopenia returned upon re-exposure to the implicated drug. This adaptation of SPRCA provides a simple means of investigating the possibility of DDPAs and documents a higher frequency of these antibodies than has previously been suspected.

Semiautomation of platelet HPA-1a phenotyping by SPRCA and ELISA

An enzyme-linked immunosorbent assay (ELISA) and solid phase red cell adherence assay (SPRCA) were assessed for platelet HPA-1a typing in U well microplates. Both methods were partially automated by the use of the Tecan RSP 8051ID robotic sampler and the SLT 400 ATC plate reader with Soft2000 software. Pretreatment of the adherent platelets with chloroquine diphosphate or citric acid enabled anti-HPA-1a, even when contaminated with HLA class 1 antibodies, to be used for typing. Of 675 antenatal samples, 13 were identified as HPA-1a negative. A further 36 known donor HPA-1a negative samples were correctly typed by both methods. Concordant results were obtained for the ELISA and SPRCA. All presumed HPA-1a negatives were confirmed by either polymerase chain reaction using sequence-specific primers (PCR-SSP) or by monoclonal antibody-specific immobilization of platelet antigens (MAIPA). The two semiautomated systems provide simple, accurate, reproducible, and secure ways for large scale HPA-1a phenotyping. The SPRCA can also be performed as a manual technique for small batches of samples.

Case report: solid-phase platelet crossmatching to support the alloimmunized patient

Abstract Platelet crossmatching by a solid-phase red cell adherence assay was used to provide compatible platelets for two alloimmunized patients with leukemia. In this study, a successful platelet transfusion was defined as giving a corrected count increment (CCI) of &gt;7,500 in a posttransfusion sample. For patient A, a total of 205 random platelet concentrates (PCs) were crossmatched. Eleven were considered compatible. These 11 PCs were transfused during five transfusion episodes. Four of the five transfusions produced CCIs of &gt;7,500 and were considered successful. Individually, eight of the eleven units were considered in vivo compatible, and five of the eight donors of these units agreed to become apheresis donors. Platelets from three of these five apheresis donors gave CCIs of &gt;7,500. For patient B, 1,074 random PCs were crossmatched, and 332 were considered compatible. These units were administered during 78 different transfusions. Seventy-one of these transfusion episodes resulted in CCIs of &gt;7,500. In addition, 19 apheresis donors were identified by platelet crossmatching, and they provided platelets for 38 of 39 successful transfusions for Patient B. Platelet crossmatching should therefore be considered when a blood bank is called upon to support a refractory thrombocytopenic patient. Immunohematology 1995;11:150–152.

Trimeresurus venom inhibition of anti-HPA-1a and anti-HPA-1b antibody binding to human platelets

Abstract A solid-phase red cell adherence assay was used to demonstrate the specific inhibitory effect of seven species of Trimeresurus snake venom on the binding of HPA-1a- and HPA-1b-specific platelet antibodies. Trimeresurus venom did not inhibit the binding of HLA-, HPA-3a-, HPA-3b-, HPA-4a-, HPA-5a-, and HPA-5b-specific platelet antibodies. Venom from other genera of snakes, including representatives from Agkistrodon, Ancistrodon, Bitis, Bothrops, Bungarus, Causus, Crotalus, Dendroaspis, Ecis, Micrurus, Naja, Notechis, Ophiophagus, Pseudechis, Sepedon (Hemachatus), and Vipera, all failed to specifically inhibit anti-HPA-1a and HPA-1b binding. These results may indicate that the component in Trimeresurus snake venom previously reported to bind to the platelet GPIIb-IIIa complex, inhibiting fibrinogen binding, binds close to the HPA-1a and HPA-1b epitopes. Immunohematology 1995;11:129–132.

Detection of drug-dependent platelet antibodies by use of solid-phase red cell adherence techniques

Abstract Many drugs have been reported to cause drug-dependent thrombocytopenia, either by the immune complex or by hapten mechanisms. Testing for the presence of these platelet antibodies has not been considered feasible for transfusion services because their presence was thought to be rare, and their detection involved complex and costly methods. We have developed a new technique for detection of these antibodies that can be performed without the need for specialized and expensive instrumentation. A solid-phase red cell adherence assay was used to detect drug-dependent platelet antibodies active by either the immune complex or the hapten mechanism. Three cases were evaluated for the presence of drug-dependent platelet antibodies. Two patients presented with thrombocytopenia that could not be attributed to other causes. The third case was evaluated for the presence of drug-dependent antibodies after poor responses to platelet transfusions. In these three cases, discontinuation of the implicated drugs, i.e., porcine heparin, quinine sulfate, amoxicillin, BactrimTM, and albuterol, was followed by a correction of thrombocytopenia or improved platelet transfusion response within 72 hours. This test methodology and protocol has proven very useful in avoiding transfusions with little likelihood of benefit, and in identifying drugs interfering with platelet recovery or survival. Further investigations with this technique may expand our knowledge of the capability of this technique and of the observed frequency of drug-related immunologic platelet destruction. Immunohematology 1995;11:143–149.