Influence of anticoagulants on the measurement of S100B protein in blood

OBJECTIVE: Evaluate anticoagulants influence on plasma S100B levels. DESIGN AND METHODS: Blood were collected from 18 healthy adult subjects using: no anticoagulants, EDTA, heparin, and citrate. S100B levels were determined using LIA-mat assay. RESULTS: Heparin plasma and citrate increased plasma S100B levels (p < 0.001), whereas EDTA had no effect (p = 0.24). Heparin plasma samples were highly (r2 = 0.97, p < 0.001), citrate samples were moderately (r2 = 0.49, p < 0.001), and EDTA samples were not (r2 = 0.22, p = 0.059) correlated with serum samples. CONCLUSIONS: When anticoagulant is required, heparin plasma should be the primary choice for measurement of S100 B levels.     

Influence of anticoagulants on the measurement of S100B protein in blood

OBJECTIVE: Evaluate anticoagulants influence on blood S100B levels. DESIGN AND METHODS: Blood from 18 healthy adult subjects were collected using: no anticoagulants; EDTA; heparin; and citrate. S100B levels were determined using LIA-mat assay. RESULTS: Heparin and citrate increased S100B levels (p<0.001), whereas EDTA had no effect (p=0.24). Heparin samples were highly (r2=0.97, p<0.001), citrate samples were moderately (r2=0.49, p<0.001), and EDTA samples were not (r2=0.22, p=0.059) correlated with serum samples. CONCLUSION: When anticoagulant is required, heparin should be the primary choice.     

Blood specimen collection methods influence the concentration and the diagnostic validity of matrix metalloproteinase 9 in blood.

BACKGROUND: Matrix metalloproteinases (MMP) in blood are promising new diagnostic tools. It was shown that the blood sampling process resulted in different blood concentrations of MMPs. To clarify whether the sampling process also influences the diagnostic validity of MMPs, MMP-9 measurements were performed in plasma and serum samples of patients with prostate carcinoma and renal cell cancer. METHODS: MMP-9 ELISAs were performed in samples of heparin plasma and serum collected in blood tubes with and without clot accelerator. Measurements were undertaken in 78 healthy persons, 33 patients with prostate carcinoma and 33 patients with renal cell carcinoma. RESULTS: MMP-9 showed higher concentrations in serum samples than in heparin plasma and was about threefold higher in serum samples collected in tubes with clot activator than in native serum samples. Both patient groups had lower MMP-9 concentrations in serum, whereas in plasma, patients with renal cell carcinoma had higher, but patients with prostate cancer unchanged MMP-9 concentrations. 13 of 33 patients with renal cell carcinoma had increased MMP-9 plasma values but no patient had increased serum concentrations. CONCLUSIONS: To optimise the diagnostic validity of the MMP-9 in blood, measurements should be performed in heparin plasma but not in serum.     

Effects of anticoagulants on the activity of gelatinases

OBJECTIVES: To identify the best procedure for preanalytical blood collection in the determination of matrix metalloproteinase (MMP)-2 and -9 by testing the effects of anticoagulants on their activity. DESIGN AND METHODS: Active forms of both gelatinases were measured by specific activity assay systems in serum, plasma EDTA, plasma-heparin and plasma-citrate obtained from 20 healthy volunteers, as well as in a pooled serum sample before and after anticoagulant treatment. RESULTS:: Active MMP-2 and MMP-9 mean concentrations were similar in serum and in plasma-citrate, higher in plasma EDTA than in serum, in plasma-heparin and in plasma-citrate, and lower in plasma-heparin than in serum and plasma-citrate. A similar trend was observed in untreated and treated pooled serum samples. CONCLUSIONS: Our results indicate that MMP-2 and MMP-9 in their active forms are not released by platelets during blood clotting, whereas the use of calcium chelating anticoagulants can profoundly alter the activity of endogenous gelatinases. This suggests that the determination of active forms of MMP-2 and MMP-9 in serum samples represents a suitable procedure.     

Pseudothrombocytopenia in plateletpheresis donors

BACKGROUND: EDTA pseudothrombocytopenia (PTCP) is an in vitro artifact in which the anticoagulation of blood with EDTA is associated with in vitro agglutination of platelets, resulting in a spuriously low platelet count. In apheresis donors, whole-blood samples for complete blood counts are routinely drawn into tubes anti-coagulated with EDTA. STUDY DESIGN AND METHODS: Records of apheresis donors were examined to identify persons in whom the postdonation counts were less than 100 × 10(9) per L. Identified donors were studied to confirm the presence of PTCP by drawing blood samples into EDTA, heparin, and trisodium citrate for serial platelet counts at room-temperature incubation. Platelet counts in citrated plasma were measured before and after the addition of EDTA. A single HLA-matched component from an identified PTCP donor was monitored for response by corrected count increment in the recipient. RESULTS: A total of nine donations were identified, involving 2 donors from a population of 945 donors (prevalence 0.2%). On testing, both donors were confirmed to have PTCP. The addition of EDTA to citrated plasma did not affect the platelet count. Response in a recipient to an HLA-matched component showed an acceptable corrected count increment. CONCLUSION: PTCP may occur in plateletpheresis donors and result in needless medical referral or donor deferral. PTCP does not appear to alter the yield content of the component or to be passively transferred to a recipient.     

Anticoagulants affect matrix metalloproteinase 9 levels in blood samples of stroke patients and healthy controls

ObjectivesMatrix metalloproteinase-9 (MMP-9) represents a promising marker for acute stroke management. In clinical studies MMP-9 has been quantified by ELISA using differing protocols. We aimed to establish a valid protocol by evaluation of preanalytics.Design and methodsBlood from stroke patients (n = 28) and healthy controls (n = 28) was drawn into tubes containing different anticoagulants (EDTA, citrate, lithium-heparin (heparin) and heparin with proteinase inhibitors) and processed after 0, 60 and 240 min. MMP-9 plasma protein and mRNA from mononuclear leukocytes were determined.ResultsIn regard to anticoagulants used, samples showed different MMP-9 protein baseline values and kinetics. Stable MMP-9 protein concentrations were only measured from EDTA samples. Particularly in samples with proteinase inhibitors protein and mRNA concentrations increased over time. Kinetics did not differ between patients and controls.ConclusionsPreanalytics plays a key role for determination of MMP-9. EDTA seems to be a valid anticoagulant for MMP-9 protein measurement.     

Effect of anticoagulants and storage temperatures on stability of plasma and serum hormones

OBJECTIVES: To determine the effect of different anticoagulants and storage conditions on the stability of hormones in plasma and serum. DESIGN AND METHODS: Human blood samples were collected from volunteers into EDTA, lithium heparin, sodium fluoride/potassium oxalate, or tubes without anticoagulant, plasma and serum left at -20 degrees C, 4 degrees C or 30 degrees C for 24 and 120 hours then assayed for ACTH, aldosterone, alpha-subunit, AVP, CRH, C-peptide, estradiol, FSH, glucagon, GH, IGF-1, IGFBP-3, insulin, leptin, LH, PPP, PTH, prolactin and VIP, or at room temperature for 0 to 72 hours (BNP, NT-BNP)(n = 6 per condition). RESULTS: The anticoagulant altered the measured concentrations for 9 hormones when compared to EDTA. All hormones except ACTH were stable for > 120 hours in EDTA or fluoride at 4 degrees C, but only 13 hormones were stable in all anticoagulants. At 30 degrees C, 8 hormones were stable for > 120 hours in EDTA, and 3 hormones in all anticoagulants. BNP and NT-BNP were stable for < 24 hours when stored in EDTA or heparin at room temperature. DISCUSSION: Storage of samples in EDTA plasma at 4 degrees C is suitable for most hormones (except ACTH) for up to 120 hours.     

Measurement of beta-2-microglobulin in serum and plasma by an enzyme-linked immunosorbent assay (ELISA)

A simple technique for the measurement of beta-2-microglobulin (beta 2M) in serum was developed. The method was designed as a sandwich technique using rabbit anti-human antibodies, employing commercially available reagents in an enzyme linked immunosorbent assay (ELISA). The assay was of high specificity, sensitivity, accuracy and reproducibility. beta 2M in serum was strongly correlated with age (p less than 0.005), but independent of sex. Values in heparin and citrate plasma were significantly lower than in serum (p less than 0.001), whereas values in serum and EDTA plasma were similar. Release of beta 2M from normal blood cells was not observed in vitro before the test procedure. An excellent correlation between the results obtained in the ELISA and a RIA was demonstrated (rS = 0.99, p less than 0.0001).     

Measurement of Elecsys NT-proBNP in serum, K2 EDTA and heparin plasma

OBJECTIVE: There is controversial evidence on a matrix influence on the measurement of NT-proBNP. DESIGN AND METHODS: We compared results of Elecsys NT-proBNP measurement on serum, K2 EDTA plasma and lithium heparin plasma. RESULTS: Samples collected in K2 EDTA showed a marginally significant underestimation when compared to serum and heparin, whereas no significant difference was observed between serum and heparin plasma. CONCLUSIONS: Serum, heparin and K2 EDTA plasma may be suitable for NT-proBNP measurement.     

Physiological matrix metalloproteinase concentrations in serum during childhood and adolescence, using Luminex Multiplex technology.

Matrix metalloproteinases are a family of zinc-dependent proteinases which are involved in the breakdown and remodeling of extracellular matrix. As children grow and adolescents reach pubescence, their bodies undergo changes that require age-related morphogenesis of the extracellular matrix, possibly requiring unique patterns of matrix metalloproteinase (MMP) expression during periods of rapid tissue growth (i.e., childhood) or accelerated tissue remodeling and expansion (i.e., adolescence). Therefore, we have characterized age-specific and gender-specific differences in circulating concentrations of MMPs (specifically MMP-1, -2, -3, -8 and -9) in 189 serum samples obtained from healthy subjects, aged 2-18 years. MMP concentrations were measured using Fluorokine MultiAnalyte Profiling kits and a Luminex Bioanalyzer, as well as by commercial ELISA. Serum levels of MMP-1, -2, -3, -8, and -9 in healthy pediatric subjects represent log-normal distributions. MMP-2 was significantly negatively correlated with age (r=-0.29; p<0.001), while MMP-3 was significantly positively correlated with age (r=0.38; p<0.001). Although plasma, not serum, is considered the appropriate blood sample for measurement of MMP-8 and -9, serum levels of MMP-8 and -9 were also found to be highly positively correlated with each other (r=0.76; p<0.01). MMP results obtained by Fluorokin MultiAnalyte Profiling methods correlated well with conventional ELISA methods and use of this technology provided several advantages over ELISA.     

Inverse relationship between markers of nitric oxide formation and plasma matrix metalloproteinase-9 levels in healthy volunteers

BACKGROUND: Nitric oxide (NO) is a major regulator of cardiovascular homeostasis and has anti-atherogenic properties. Reduced NO formation is associated with endothelial dysfunction and with cardiovascular risk factors. Although NO downregulates the expression and activity of the pro-atherogenic enzyme matrix metalloproteinase-9 (MMP-9), no previous clinical study has examined whether endogenous NO formation is inversely associated with the circulating levels of pro-MMP-9, which are associated with cardiovascular events. We examined this hypothesis in 175 healthy male subjects who were non-smokers. METHODS: To assess NO bioavailability, the plasma concentrations of nitrite, nitrate, and cGMP were determined using an ozone-based chemiluminescence assay and an enzyme immunoassay. Pro-MMP-9 and pro-MMP-2 levels were measured in plasma samples by gelatin zymography. RESULTS: We found significant negative correlations between pro-MMP-9 levels and plasma nitrite (P=0.035, rs= -0.159), nitrate (P=0.040, rs= -0.158), and cGMP (P=0.011, rs= -0.189) concentrations. However, no significant correlations were found between pro-MMP-2 levels and the plasma concentrations of markers of NO bioavailability (all P>0.05). CONCLUSIONS: There is an inverse relationship between markers of NO formation and plasma MMP-9 levels. This finding may shed some light on the possible mechanisms involved in the increased cardiovascular risk of apparently healthy subjects with low NO bioavailability or high circulating levels of pro-MMP-9.     

Matrix metalloproteinase-9 (gelatinase B) is elevated during mobilization of peripheral blood progenitor cells by G-CSF

BACKGROUND: Matrix metalloproteinase-9 (MMP-9 or gelatinase B) has recently been implicated in the IL-8-induced mobilization of HPCs in rhesus monkeys and mice. It is not known whether administration of G-CSF causes expression of MMP-9 during HPC mobilization. STUDY DESIGN AND METHODS: Blood samples from 15 allogeneic progenitor cell donors were collected before and during G-CSF-induced HPC mobilization. The expression of the gelatinases MMP-2 and MMP-9 in the plasma of the donors was analyzed by ELISA and zymographic analysis. Gelatinolytic activity was measured with a fluorometric assay that was specific for gelatinases. Expression of IL-6, IL-8, and soluble vascular cell adhesion molecule (VCAM) was measured by ELISA. RESULTS: Highly elevated latent gelatinolytic activity was found on Days 4 and 5 of G-CSF treatment in comparison to pretreatment activity. ELISA and zymographic analyses revealed pro-MMP-9 as the major source of the latent gelatinolytic plasma activity during mobilization. Pro-MMP-2 was not elevated compared with pretreatment levels. As IL-8 has been implicated in the expression of MMP-9, IL-8 concentrations were measured in plasma samples from donors and patients immediately before the start of HPC apheresis, but no significantly elevated IL-8 concentrations were noted. In contrast, pro-MMP-9 and latent gelatinolytic activity was highly correlated with IL-6, which was strongly elevated during mobilization therapy. Finally, soluble VCAM was equally significantly elevated on the days of apheresis. CONCLUSIONS: G-CSF mobilization treatment induces MMP-9, IL-6, and soluble VCAM. Expression of MMP-9 might be involved in the mobilization of human HPCs and might be a final common pathway of different mobilization therapies. Our data do not support a role of IL-8 in G-CSF-induced mobilization. In contrast, IL-6 might be involved in the G-CSF-induced expression of MMP-9.     

Optimal conditions for collection of blood samples for assay of α2-macroglobulin trypsin complex-like substance (MTLS)

We have developed an enzyme-linked immunosorbent assay (ELISA) for the specific quantification of α2-macroglobulin-trypsin complex-like substance (MTLS). To exclude artifacts in measured values of MTLS, the conditions for collection of blood samples are critical. In the present study, we have determined the optimal conditions for blood collection and investigated the role of MTLS as a clinical tool for diagnosis in pancreatitis. Results obtained are as follows: (1) MTLS levels of all sera were more than 10-fold higher than the corresponding plasma; (2) MTLS levels of heparinized plasma were the lowest among plasma with three anticoagulants (sodium citrate, sodium EDTA and heparin); (3) some kinds of blood collection tubes containing heparin were not suitable for the sampling; (4) MTLS values of plasma obtained by blood collection tubes containing Trasylol® and sodium EDTA were demonstrated more stable and lower than those obtained by heparin tubes; and (5) under these conditions, we can exclude elevation of MTLS values caused by inappropriate blood sampling and find the time course of the elevation reflecting clinical course of a patient with acute pancreatitis and a patient after endoscopic retrograde cholangiopan-creatography (ERCP). The optimal conditions for collection of blood samples were as follows. Blood sampling should be performed by blood collection tubes containing Trasylol® (50 μl/ml blood) and sodium EDTA (1.5 mg/ml blood). The samples were immediately stored at 4°C and centrifuged at 3,000 rpm for 15 min. The plasma were stored in plastic tubes at 4°C until assayed. © 1996 Wiley-Liss, Inc.     

不同抗凝剂对肝移植受者FK506血药浓度测定的影响及临床意义

目的探讨不同抗凝剂对肝移植受者他克莫司（FK506）血药浓度测定的影响及临床意义。方法采集肝移植受者静脉全血34份,使用乙二胺四乙酸二钾（EDTA-K2）、枸橼酸钠和肝素锂抗凝剂分别抗凝同一份血样本,在IMx型免疫分析仪上用微粒子酶免疫分析法（MEIA）测定FK506血药浓度。结果肝素锂组与EDTA组差异无统计学意义（P=0.660）,呈正相关（r=0.982 8）。枸橼酸钠组与EDTA组差异有统计学意义（P=0.000）,呈正相关（r=0.961 3）。枸橼酸钠组与肝素锂组差异有统计学意义（P=0.000）,呈正相关（r=0.939 8）。结论肝素锂组与EDTA组几乎无偏差,但是枸橼酸钠组分别与EDTA组和肝素锂组存在一定程度的负偏差。枸橼酸钠对MEIA测定FK506血药浓度有一定的影响,应优先考虑EDTA或肝素锂抗凝剂采集全血样本。     

Effect of collection tube type and preanalytical handling on myeloperoxidase concentrations

BACKGROUND: Myeloperoxidase (MPO) has shown potential as a marker for cardiovascular disease. Limited studies have been published with a variety of sample types, resulting in a wide range of MPO values. Little is known or understood about the impact of collection tube type and preanalytical handling of specimens for MPO determination. METHOD: MPO concentration was determined by use of the ARCHITECT(R) MPO research use assay, which is currently under development. Samples were collected into multiple anticoagulant collection tubes from donors and patients presenting to the emergency department with symptoms of acute coronary syndromes. Whole blood was stored on ice or at room temperature for predetermined time periods. We also evaluated serum and plasma after centrifugation followed by storage at room temperature, 2-8 degrees C, and below -10 degrees C. RESULTS: Baseline sample concentrations were dependent on collection tube type as well as handling conditions. MPO concentrations were consistently higher in samples collected in serum and heparin plasma tubes than in samples in EDTA or citrate tubes. Spike recovery was acceptable in all sera and plasma tested, indicating that the increased MPO concentrations were not due directly to an anticoagulant interference. CONCLUSIONS: The collection tube type and preanalytical handling are critical for accurate and consistent MPO measurement. The preferred anticoagulant and tubes are the EDTA or EDTA plasma preparation tube. MPO concentrations in samples collected in these tubes are stable before centrifugation as whole blood as well as plasma after processing.     

Influence of pre-analytical and analytical factors on soluble CD40L measurements

The soluble form of CD40L (CD40 ligand), a pro-atherogenic mediator, has emerged as a diagnostic and prognostic marker for cardiovascular events. However, as platelets can shed CD40L upon activation, accurate measurement has proved challenging. The present study addresses the controversy regarding the appropriate specimen and preparation for laboratory evaluation of blood sCD40L (soluble CD40L). Serum and plasma (collected in EDTA, citrate or heparin) were collected from healthy volunteers (n=20), and sCD40L was analysed by ELISA immediately or after one to three freeze-thaw cycles and at different centrifugation speeds. Urine sCD40L levels were measured in subjects with low- and high-plasma sCD40L levels. Serum sCD40L levels (5.45+/-4.55 ng/ml; P<0.001) were higher than in citrate, EDTA or heparin plasma (1.03+/-1.07, 1.43+/-1.03 or 1.80+/-1.25 ng/ml respectively), with no significant differences between plasma preparations. Increasing g values (200-13000 g), which gradually deplete plasma of platelets, yielded lower sCD40L levels. Repeated freeze-thaw cycles significantly (P<0.05) increased sCD40L concentrations in platelet-rich, but not platelet-depleted, plasma (up to 2.4-fold). Bilirubin and haemoglobin interfered positively, and triacylglycerols (triglycerides) and cholesterol quenched CD40L signalling. No sCD40L was detected in urine samples. In conclusion, serum yields higher sCD40L concentrations than plasma; accurate measurements of sCD40L require exclusion of platelets and avoiding their post-hoc activation. Samples with high concentrations of bilirubin, haemoglobin and/or triacylglycerols should be excluded, as these substances interfere with the assay.     

6项临床化学指标适用血浆样本类型的研究

目的 研究不饱和铁结合力（UIBC）、β-羟丁酸（β-HB）、肌红蛋白（MYO）、丙氨酸氨基转移酶（ALT）、铁（Fe）和磷（P）试剂盒可接受的血浆样本类型.方法 使用血清、肝素血浆和EDTA血浆采血管,收集研究对象静脉血样本.样本离心处理后,在BS-800全自动生化分析仪上,分别检测血清和血浆样本中UIBC,β HB,MYO,ALT,Fe和P的水平,并对血清和血浆样本结果进行统计学分析.结果 血清样本组UIBC,β HB,MYO测定结果（34.4±9.8 μmol/L,0.41±0.92mmol/L和48.0±21.6 ng/ml）与肝素血浆样本组（34.6±10.2 μmol/L,0.41±0.92 mmol/L和46.7±20.1 ng/ml）比较差异无统计学意义（t=0.77, 0.88和1.33,P均＞0.05）,血清样本组MYO测定结果（113.2±118.0 ng/ml）和EDTA血浆样本组（113.0±116.3 ng/ml）比较差异无统计学意义（t=0.25,P＞0.05）.血清样本组ALT,Fe和P测定结果（76.9±155.7 U/L,17.7±16.3 μmol/L和1.14±0.15 mmol/L）与肝素血浆样本组（76.3±155.8 U/L,17.9±16.3 μmol/L和1.11±0.15 mmol/L）比较差异有统计学意义（t=2.99,-2.25和5.61,P均＜0.05）,血清样本组P测定结果（1.14±0.15mmol/L）和EDTA血浆样本组（1.09±0.14 mmol/L）比较差异有统计学意义（t=13.46,P＜0.05）.但血清和肝素血浆ALT,Fe和P测定结果,及血清和EDTA血浆P测定结果均呈正相关（相关系数分别为0.999 9,0.999 0,0.987 5和0.9936,P均＜0.01）,在医学决定水平处的偏差（4.2％-3.2％）均小于允许误差的50％.结论 肝素血浆样本类型适用于UIBC,β HB,MYO,ALT,Fe和P试剂盒的测定,EDTA血浆样本类型适用于MYO和P的测定.     

血浆与血清标本对心肌肌钙蛋白检测的影响

目的探讨血浆与血清标本对心肌肌钙蛋白I(cTnI)检测的影响,以选用合适的标本缩短检测周转时间(TAT),优化实验规程。方法使用Beckman Coulter化学发光免疫分析仪分别检测74例患者血清、乙二胺四乙酸(EDTA)抗凝血浆、肝素抗凝血浆中cTnI水平。结果血浆与血清标本检测结果相关性良好,决定系数(r2)均为0.999。血清、EDTA抗凝血浆、肝素抗凝血浆阳性率分别为64.865%,60.811%,63.513%,三者之间比较差异无统计学意义。血清标本假阳性率为4.17%,肝素抗凝血浆假阳性率为2.13%,EDTA抗凝血浆假阴性率为3.45%。结论血浆标本对肌钙蛋白测定的影响较小。为缩短检测周转时间,优化实验规程,可考虑采用抗凝血浆代替血清。     

Relationships between the level of matrix metalloproteinase-2 and tumor size of breast cancer

BACKGROUND: The involvements of matrix metalloproteinase-2 (MMP-2) in the pathogenesis of breast cancers have been established. We determined the concentrations of MMP-2 in serum samples and tumor tissues of breast cancer patients. METHODS: Gelatin zymography and ELISA were used to measure MMP-2 and MMP-9 concentrations in 90 breast cancer patients, including 60 tissue samples and 30 serum samples. RESULTS: ProMMP-2, activated MMP-2, proMMP-9 and activated MMP-9 levels were significantly higher in tumor tissues than that of corresponding paired adjacent normal tissue of 60 breast cancer patients (p<0.01). Further linear regression analysis has showed that the tumor size positively correlated with MMP-2 level in tumor tissue samples (R=0.55, p<0.0001), as well as with that of in serum samples (R=0.398, p=0.032). In addition, further statistical analysis for clinic pathological parameters revealed that MMP-2 level was significantly increased in patients with metastasis (p<0.05). Furthermore, MMP-2 level was significantly different between tumor grades (p=0.006). CONCLUSIONS: MMP-2 levels in serum and tumor tissue might reflect the severity of invasion of breast cancer and various MMP inhibitors might be selectively used as potential anti-metastasis agents according to tumor size.     

维持性血液透析患者血清MMP-2、MMP-9检测的临床意义

目的观察维持性血液透析患者血清基质金属蛋白酶-2(MMP-2)、基质金属蛋白酶-9(MMP-9)水平的变化及临床意义。方法应用酶联免疫分析法测定60例维持性血液透析患者及30名健康体检者血清MMP-2、MMP-9的水平。结果维持性血液透析患者血清MMP2水平明显高于健康体检者(P<0.01),而MMP9水平则明显地低于健康体检者(P<0.01)。MMP-2水平与尿素氮和肌酐水平呈正相关(P<0.01),MMP-9水平与尿素氮和肌酐水平呈负相关(P<0.01)。结论检测维持性血液透析患者血清MMP2、MMP9水平的变化对尿毒症病情和预后判断均具有重要的临床价值。