Acute hemolytic transfusion reaction due to a warm reactive anti-A1.

BACKGROUND: Anti-A1 are regularly observed by reverse testing and are generally considered clinically irrelevant. For compatibility testing and the selection of blood, we use the type-and-screen (T&S) strategy, in which ABO confirmation of patients with a definitive blood group is performed by forward grouping only. Because anti-A1 seem clinically irrelevant, it is our policy to provide group A blood in patients with an anti-A1 . STUDY DESIGN AND METHODS: This is a case report of a 96-year-old woman who died shortly after transfusion of blood group A red blood cells (RBCs). She was known to have blood group A2 with an anti-A1 and the absence of other RBC antibodies. Directly after starting transfusion, acute dyspnea was observed, while other clinical signs for a transfusion reaction were absent. In the laboratory, indications for a severe hemolytic transfusion reaction (HTR) triggered serologic investigations and complement deposition experiments. RESULTS: Analyses revealed that the anti-A1 was present as a high-titer IgM class immunoglobulin that induced complement deposition on A1 RBCs. The anti-A1 reacted in a wide temperature amplitude up to 37°C with A1 RBCs, while weak agglutination was observed with A2 RBCs at room temperature. CONCLUSION: A pretransfusion detectable anti-A1 caused a severe HTR that, in view of the rapid onset of clinical symptoms and concomitant deterioration, contributed to the death of the patient. Considering its clinical significance in this case, we encourage an unambiguous procedure for patients with an anti-A1 , especially when T&S is used for donor RBC selection.

Protocolled Redefinition of the Therapeutic Range for Unfractionated Heparin: Lost in Translation?

BACKGROUND: Protocolled treatment with unfractionated heparin (UFH) is a subject of ongoing debate. Even though international guidelines prescribe calibration of the activated partial thromboplastin time (aPTT) to 0.3 to 0.7 U/mL anti-Xa activity to establish an UFH therapeutic range, evidence for this approach remains scarce. In this study, we evaluated different strategies to delineate the UFH therapeutic range and analyzed the effects on patient therapeutic classification. METHODS: In 109 patient samples, the aPTT was measured with 2 different reagents, both of which used mechanical clot detection. The UFH therapeutic range was determined using 3 previously described methods: calibration of the aPTT to 0.3 to 0.7 U/mL anti-Xa activity, application of 1.5 to 2.5 times the control aPTT, or using 0.3 to 0.7 U/mL anti-Xa activity directly. We also applied the UFH therapeutic range of a second hospital to our patient population. RESULTS: Application of the guideline-prescribed anti-Xa calibration method would result in patients receiving increased UFH dosage in comparison to our previous UFH nomogram. Between-method and between-laboratory variations in aPTT and anti-Xa activity assays are a likely cause of these discrepancies. Additionally, we show that individual patient characteristics, such as weight and UFH treatment duration, likely contribute to the discordance between different strategies to establish an UFH therapeutic range. CONCLUSION: No consensus is reached between different strategies to define the UFH therapeutic range, which could result in relevant differences in UFH doses applied in patients. Clinicians and laboratory specialists should critically evaluate UFH monitoring protocols and be aware of their shortcomings.

Collection of blood specimens by venipuncture for plasma-based coagulation assays: necessity of a discard tube.

The Clinical and Laboratory Standards Institute (CLSI) recently abandoned its recommendation for drawing a discard tube when performing a prothrombin time (PT)/international normalized ratio (INR) or an activated partial thromboplastin time (APTT). Because there is currently no evidence that a discard tube is necessary for more specialized coagulation assays, we studied the need for a discard tube for some of these tests. Blood was obtained from 88 subjects in 2 subsequent citrate tubes. Platelet-free plasma was tested for PT, APTT, antithrombin, protein C, and factors II, V, VIII, IX, and X. Difference and bias between tubes were tested using the Wilcoxon signed rank test and Bland-Altman plots. For only APTT, antithrombin, and protein C was a small, statistically significant mean bias found (0.5 seconds; P = .001; -0.7%, P = .002; and -0.8%, P < .0001, respectively), but the bias of individual samples was not clinically relevant. This was also true for the other parameters tested. The recent CLSI recommendation that a discard tube is not necessary for PT/INR and APTT can be extended to include more specialized plasma-based coagulation assays as identified in this study.

Serotonin transporter polymorphism and bleeding time during SSRI therapy.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: From case reports it has become clear that selective serotonin reuptake inhibitors (SSRIs) can cause bleeding disorders. The causative mechanism is as yet unknown. Several publications have described the relationship between the serotonin transporter genotype and the prevalence of certain diseases such as depression, but few have focused on the relationship with side-effects of antidepressive drugs such as SSRIs. WHAT THIS STUDY ADDS: This study suggests that the association between SSRI therapy and prolonged bleeding time may not be related to the polymorphism of the serotonin transporter (5-HTTLPR) investigated. AIMS: Selective serotonin reuptake inhibitors (SSRIs), such as paroxetine, are associated with an increased risk of bleeding disorders, probably due to decreased platelet serotonin levels. Polymorphisms in the serotonin transporter gene (5-HTT) may influence the risk of SSRI-induced bleedings. The aim of this study was to investigate whether and to what extent the serotonin transporter polymorphism increases the bleeding time in paroxetine users. METHODS: A prospective study, using routinely collected hospital and pharmacy data, was conducted among 43 patients between 18 and 70 years old and on >4 weeks of paroxetine therapy. The genotype for the serotonin transporter (5-HTTLPR), trough paroxetine levels, platelet function analyser (PFA)-closure time (collagen/epinephrine) and a complete blood count were assessed. RESULTS: No significant difference was seen between the SS, SL, LL genotypes of the serotonin transporter and the PFA-closure time. None of the covariates had a significant influence on the association between the serotonin transporter polymorphism and the PFA-closure time. Age and von Willebrand factor showed the largest contribution, but not significant. No difference was seen between the PFA-closure time and the frequency of bruising and spontaneous bleedings between patients with at least one S allele and with the LL genotype. CONCLUSION: Our prospective study does not support the assumption that paroxetine can cause a prolonged PFA-closure time during paroxetine therapy due to a serotonin transporter polymorphism. Old age, use of platelet inhibitors and a history of gastrointestinal bleeding remain the focus for SSRI-induced bleeding complications.

Urine flow cytometry and detection of glomerular hematuria.

BACKGROUND: The UF-100 is a flow cytometer designed for automated cellular urinalysis. In this study, the usefulness of the UF-100 in laboratory investigation into the origin of hematuria was evaluated. METHODS: Results from flow cytometric urinalysis were used to classify urinary red blood cells (RBCs) according to glomerular and non-glomerular origin and the classification was compared to the patient's clinical diagnosis as the gold standard. In parallel, microscopic sediment analysis was carried out. RESULTS: A total of 206 urine samples from 129 patients were analyzed (127 from patients with glomerular hematuria, 79 from patients with non-glomerular hematuria). Of these, 136 samples (92 patients) showed overt hematuria (>or=20 RBC/microL). Urine flow cytometry correctly classified 61% (sediment analysis 69%) of urine samples with overt hematuria. If inconclusive results are excluded, the UF-100 correctly diagnosed 85% (sediment analysis 98%) of urine samples with overt hematuria. The UF-100 and microscopic sediment analysis both showed sensitivity of 99% for the detection of glomerular hematuria. The specificity of the UF-100 for the detection of glomerular bleeding was lower (42%) than the specificity of microscopic sediment analysis (93%). CONCLUSIONS: Owing to its low specificity, the UF-100 showed limited capacity to discriminate glomerular from non-glomerular causes of hematuria in a population with a high incidence of renal disease. Therefore, extensive microscopic urinalysis remains necessary to assess the origin of hematuria.

An improved laboratory protocol to assess subarachnoid haemorrhage in patients with negative cranial CT scan.

BACKGROUND: The laboratory analysis of cerebrospinal fluid (CSF) plays a key role in considering subarachnoid haemorrhage (SAH) in patients with clinical suspicion, but negative CT scan. Although the determination of the CSF bilirubin concentration generally provides high sensitivity, it was recently shown that specificity and positive predictive value are unacceptably low, limiting its use as a diagnostic tool. METHODS: We intended to design and evaluate an improved laboratory protocol, which fulfills the requirement of better specificity without losing sensitivity. We present a procedure in which a "bili-excess" concentration is determined, which is the surplus CSF bilirubin measured after subtraction of an estimated upper limit for the individual patient. The latter is calculated from [bilirubin](serum), [albumin](serum) and [albumin](CSF), taking into account the propagation of analytical errors in the individual analyses. We investigated the applicability of direct absorption vs. derivative spectroscopy, thereby addressing the influence of various calibration methods. We evaluated our procedure in 92 CSF samples drawn from patients with (n=37) and without (n=55) clinical suspicion of SAH. RESULTS: In our study population, we show that specificity increases from 0.83 (95% CI, 0.74-0.91) to 1.00 (95% CI, 0.96-1.00) using the bili-excess concept, with an established upper limit for bili-excess of 0.11 micromol/L instead of the recommended use of an "uncorrected" CSF bilirubin upper limit of 0.20 micromol/L. Sensitivity in both cases is 1.00 (95% CI, 0.66-1.00). We demonstrate the merit of allowing for analytical imprecision in the bili-excess concept. CONCLUSIONS: We provide a quantitative procedure to explore the likelihood of (CT-negative) SAH independent of the absolute CSF bilirubin concentration by considering the "bili-excess" concentration per individual, using derivative spectroscopy to determine CSF bilirubin. This procedure led to an increase in specificity to 1.00 (95% CI, 0.96-1.00) in our study population.

Subclinical signs of vascular damage relate to enhanced platelet responsiveness among nonpregnant formerly preeclamptic women.

OBJECTIVE: In nonpregnant formerly preeclamptic women, the prevalence of occult cardiovascular abnormalities is increased. These high-risk women mildly benefit from low-dose aspirin in the prevention of recurrent disease. How this effect is mediated, either by affecting platelet or vascular function, is still unsettled. In this study, we tested the hypothesis that in these nonpregnant women, enhanced platelet responsiveness is common and related to microvascular damage. STUDY DESIGN: At least 6 months' postpartum we evaluated in 66 formerly preeclamptic women platelet count, volume, and in vitro response to low-dose ADP (0.5 microg/mL). Peripheral levels of fibronectin (microg/mL), von Willebrand factor antigen (%), C-reactive protein (high-sensitive CRP, mg/L), urinary albumin, and protein (24-hour collection, g/mol creatinine) served as markers of vascular damage. Hemodynamic function was determined by plasma volume (iodine I 125 HSA indicator dilution method, mL/kg lean body mass), cardiac index (Doppler, mL/min/m2), blood pressure and heart rate (Dinamap [Critikon, Tampa, FL], mm Hg and beats/min, respectively). Thereafter, we subdivided these 66 women into 2 subgroups either with (n = 10, 15%) or without increased platelet responsiveness (n = 56, 85%). Both groups were compared nonparametrically. RESULTS: Groups were comparable with respect to age, blood pressure, body mass index, parity, plasma volume, and cardiac index. Women with enhanced platelet responsiveness had higher levels of circulation fibronectin and CRP, and displayed more often albuminuria and proteinuria. In addition, even though platelet count was comparable between groups, the mean platelet volume was higher among women with enhanced platelet responsiveness. CONCLUSION: Fifteen percent of formerly preeclamptic women had enhanced platelet responsiveness, which was associated with elevated levels of various markers for (micro) vascular damage. We speculate that in these women platelets are presensitized on a relatively dysfunctional endothelium. Although this association does not prove causality, these results may indicate a subgroup of women who benefit from low-dose aspirin in the prevention of recurrent disease in a next pregnancy.

Do we measure bilirubin correctly anno 2005?

We observed 30% discrepancy between liquid chemistry and dry chemistry analysers for the determination of total bilirubin in human adult serum samples, which were consistent with a 20% overestimation and 10% underestimation relative to a Jendrassik-Grof reference method, respectively. In contrast, standard reference material SRM916, which was recently recommended as being the most suitable material for attaining interlaboratory agreement, shows very good agreement on both types of analysers, as well as close to 100% recovery with respect to the reference method. We show that the liquid vs. dry bilirubin discrepancies seem to originate in the presence of either conjugated or delta-bilirubin. Our observations make it clear that good interlaboratory (or inter-analyser) agreement between bilirubin reference materials does not guarantee the same for bilirubin concentrations in human serum samples.

The effect of flavoring oral rehydration solution on its composition and palatability.

OBJECTIVE: As a number of mild to moderately dehydrated children refuse to drink oral rehydration solution (ORS) because of its strong salty taste, many parents and health workers flavor ORS with the childs favorite juice. The effects of flavoring ORS on electrolyte content and osmolality were assessed and the palatability of various solutions were compared with commercially flavored ORS. METHODS: Osmolality, sodium, potassium, chloride and glucose content after flavoring with varying concentrations of apple juice, orange juice or orangeade was determined. Two of the solutions were offered to 30 children and adults to assess palatability. RESULTS: All additions to ORS (apple juice, orange juice or orangeade) caused a decrease of sodium (-30 to -53 mmol/L) and chloride (-27 to -47 mmol/L) content, whereas osmolality increased to greater than 311 mOsm/kg. These homemade oral rehydration solutions did not fulfill ESPGAN criteria for ORS, and rehydration will therefore be less effective. The majority of subjects also preferred the commercially flavored ORS. CONCLUSION: Only very small amounts of apple juice or orange juice can be added to the ORS without significantly altering electrolyte composition and osmolality. Palatability, however, does not improve compared with commercially flavored ORS. We therefore recommend using commercially flavored ORS, the composition of which fulfills ESPGAN criteria.

Inflammatory response in the acute phase of deep vein thrombosis.

OBJECTIVE: Deep vein thrombosis (DVT) is a multifactorial disease. Recently, inflammation has been suggested as a risk factor for DVT. The question is whether inflammation is a cause of venous thrombosis or rather a result of the thrombotic process. METHODS: We studied the inflammatory response in the acute phase of DVT with interleukin-6, interleukin-8, and C-reactive protein (CRP) as inflammatory markers. Plasma concentrations were measured on the day of admission (day 0) in 40 patients with acute DVT confirmed with phlebography and in 33 patients with clinical suspicion of DVT but negative phlebography results (controls). In patients with DVT, inflammatory markers were also examined on five subsequent days. RESULTS: On day 0, the median concentrations in plasma of interleukin-6, interleukin-8, and CRP were 15.0 pg/mL (range, <3 to 70 pg/mL), 7.0 pg/mL (range, <3 to 76 pg/mL), 37.5 mg/L (range, <7 to 164 mg/L), respectively, in the patient group and less than 3 pg/mL (range, <3 to 11 pg/mL; P <.001), 6.0 pg/mL (range, <3 to 52 pg/mL; P =.08), and 5.0 pg/L (range, <7 to 66 pg/L; P <.001), respectively, in the controls. During the next days, interleukin-6 concentration showed a gradual decline in patients with DVT from 15.0 to 5.5 pg/mL (P <.001), interleukin-8 concentration was relatively constant in time, and CRP concentration declined from 37.5 to 21.5 mg/L (P =.01). CONCLUSION: Our data show an apparent inflammatory response with highest measured concentrations of inflammatory markers on the day of admission and a subsequent decrease during the next days. This response supports the hypothesis that elevated inflammatory markers are a result rather than a cause of venous thrombosis.