Red cell pyruvate kinase deficiency: An optimised assay

As a result of using a variety of assay techniques, rather different values for the rate of the pyruvate kinase (PK) reaction were obtained. Kinetic measurements performed with red cell PK using the stopped-flow as well as the “classical” spectrophotometric method demonstrated that only the initiation of the reaction with ADP yields reproducible results in the standard assay. Moreover, the influence of substrate concentrations, activator concentrations, ionic strength, buffer system, temperature and duration of preincubation were thoroughly investigated and were shown to play an important role. As a consequence of our kinetic measurements, a modified optimised assay composition together with new normal values for erythrocyte PK activity in haemolysate are presented. For better characterisation and comparability of PK variants, we suggest the use of the optimised assay composition described and that the reaction be initiated with ADP.     

外周血基因转录本检测中2种标本处理方法的比较

目的　选择合理的标本处理方法 ,提高外周血基因转录本检测的灵敏度。方法　 5 3例胃癌患者外周血标本分别以淋巴细胞分离液 (FICOLL)和红细胞裂解液 (RLS)处理后提取RNA ,以荧光定量RT PCR技术检测 β actin基因和CEA基因转录本。 结果　RLS法和FICOLL法定量检测 5 3例外周血标本的 β actin基因转录本的平均浓度分别为 1.19× 10 6和 2 .4 0× 10 5拷贝 /ml,2组测定值差异有显著性 (P <0 .0 1)。RLS法检测 5 3例中 13例为CEAmRNA阳性 ,阳性率为 2 4 .5 % ;FICOLL法检测到 5例阳性 ,阳性率 9.4 % ,RLS法的阳性检出率高于FICOLL法 (P <0 .0 5 )。结论　RLS法分离外周血有核细胞的效果优于FICOLL法 ,有利于提高基因表达检测的灵敏度。     

Value of an enzymatic assay for the determination of serum ceruloplasmin

The serum concentration of the copper protein ceruloplasmin has been an important diagnostic indicator of Wilson's disease (WD). It is widely quoted that 95% of people with WD have low serum ceruloplasmin concentrations. Current evidence suggests that a normal serum ceruloplasmin concentration is more common in patients with WD, particularly those with liver disease, perhaps in part because of the routine use of an immunologic assay. This assay might indicate a normal level of ceruloplasmin when the enzymatic activity is lower. Enzymatic activity is the biologically relevant parameter. We compared the immunologic measurement with the enzymatic assessment of oxidase activity in patients with liver or neurologic symptoms of unknown origin in whom WD was considered in the differential diagnosis. Although a strong correlation of ceruloplasmin protein concentration with oxidase activity was observed in controls, this was not the case for these patients. Twelve patients, presenting with various types of hepatic disease, demonstrated a weak correlation between ceruloplasmin protein concentration and oxidase activity. Ten percent of patients with neurologic symptoms ( n = 41) had low ceruloplasmin concentrations and oxidase activity, and another 8% had normal ceruloplasmin concentrations associated with low oxidase activity. Although the enzymatic method is preferred for its biologic relevance, ceruloplasmin analysis is not a reliable diagnostic parameter for the diagnosis of WD in patients with liver disease. An important use of the ceruloplasmin oxidase assay is in the follow-up of patients with WD. Ceruloplasmin oxidase activity was undetectable in sera from patients with WD who were undergoing long-term chelation therapy, suggesting an early sign of copper depletion and a need for subsequent monitoring for symptoms of copper deficiency.     

Evaluation of a concurrent multicomponent collection system for the collection and storage of WBC-reduced RBC apheresis concentrates

BACKGROUND: Multicomponent apheresis procedures offer the possibility of collecting blood components that are standardized, as compared to those available with whole-blood donations. A new separator program for the concurrent collection of RBCs, platelets, and plasma (Amicus, Baxter Healthcare) was evaluated. STUDY DESIGN AND METHODS: Apheresis donors (n = 47) underwent concurrent collection of RBCs, platelets, and plasma by use of the single-needle procedure of the Amicus blood cell separator. A standardized RBC volume (100% Hct) of 200 mL was targeted with either 1 or 2 platelet concentrate units, depending on the donor's predonation characteristics. After collection, the RBC component was sterilely connected to an RBC collection set (Amicus) to allow for the addition of 100 mL of saline-adenine-glucose-mannitol preservative solution and WBC reduction at either ambient temperature or 4 degrees C. The RBC units were subsequently stored at 2 to 6 degrees C for 42 days, and the following in vitro measures were evaluated over the storage period: blood cell counts including Hct and total Hb, plasma Hb, potassium, pH, ATP, and 2,3 DPG. RESULTS: Procedure time averaged 74 +/- 9 minutes, and no adverse events were reported. The absolute RBC volume collected averaged 198 +/- 11 mL with an average Hct value of 83 +/- 2 percent. After filtration, the Hb content averaged 58.2 +/- 2.4 g per unit and residual WBCs averaged 0.038 +/- 0.015 x 10(6) per unit. Day 42 results showed that all units had on average more than 70-percent ATP maintenance, and all of the units had less than 0.8 percent he-molysis. All units had pH values higher than 6.5 on Day 42. CONCLUSION: The concurrent multicomponent collection system (Amicus) can reliably collect a standardized RBC unit of good quality. In vitro testing of the RBCs collected and stored for 42 days met the Council of Europe criteria for transfusion.     

Glucose-6 phosphate dehydrogenase deficiency: an easy and sensitive quantitative assay for the detection of female heterozygotes in red blood cells

Different methods for the quantitative determination of glucose-6-phosphate dehydrogenase (G-6-PD) were compared and one of them found to be highly precise. Maleimide inactivation of 6-phosphogluconate dehydrogenase (PGD) was investigated. It was shown that this inactivation is time-dependent and causes loss of assay precision. The most precise method was adapted to lysates of red blood cells from females, known to be heterozygote for G-6-PD deficiency and from non-deficient males and females. Heterozygote gene carriers were detected at a rate of 97.0%.     

用ELISA检测抗丙酮酸脱氢酶复合物E2和E3结合蛋白自身抗体

目的　用重组丙酮酸脱氢酶复合物E2亚单位和E3结合蛋白 (PDC E2 ,PDC E3BP)建立筛查原发性胆汁性肝硬化 (PBC)患者相应自身抗体的ELISA。方法　用本室制备的重组PDC E2和PDC E3BP蛋白包被酶联反应板 ,检测PBC患者、正常人及其他肝病患者血清。结果　组建成筛查PBC患者血清中自身抗体的试剂盒 ,能够准确地检测PBC患者血清中的自身抗体。结论　建立的试剂盒能用于PBC患者血清中丙酮酸脱氢酶复合物自身抗体的检测。     

Prognostic factors for predicting severity and mortality in hospitalized COVID‐19 patients

BackgroundCoronavirus disease 2019, COVID‐19, has reached all the corners of the world and was declared by the WHO as a global pandemic and public health emergency of international concern on the January 31, 2020. Allocating quick and specific biomarkers to predict the disease severity upon admission to hospital became a crucial need. This study, therefore, aimed at exploring the relationship between laboratory results in COVID‐19 patients admitted to hospital and the final outcome in these patients.MethodsRetrospective analysis was performed on the medical records of 310 COVID‐19‐positive patients admitted to Uhod Hospital, the referral hospital in the area of Madinah, Kingdom of Saudi Arabia, between the April 13 and the July 29, 2020. The association of laboratory results with the survival/mortality outcomes was studied.ResultsIt was demonstrated that lymphopenia, prolonged aPTT, high INR, high D. dimer and high CK are valuable prognostic predictors of the severity of the disease at early stages that can determine the outcome. Based on the results of the multiple logistic regression, the variables that are associated with death outcome are aPTT, HR, RR, ALT and CK levelConclusionIt is proposed to perform these tests on admission to hospital for moderate to severe COVID‐19 patients to improve the management of those cases and reduce mortality.     

Enzymatic pattern of glucose metabolic pathways in pyruvate kinase-deficient erythrocytes.

It has been shown that in some cases of congenital non-spherocytic haemolytic anaemia (CNSHA) with pyruvate kinase deficiency, the primary defect may be related to diminished magnesium-stimulated ATPase activity, followed by elevation of the erythrocyte ATP level. ATP as the end product of glycolysis inhibits by negative feedback control the activities of key glycolytic enzymes involved in energy production, i.e. pyruvate kinase (PK) and phosphofructokinase (PFK). Erythrocyte-deficient PK, however, is insensitive to the stimulating effect of fructose 1,6-diphosphate (FDP), which is normally a positive effector of PK. Both competing effectors, i.e. ATP and FDP, seem to show specific interaction. PK, inactive in the presence of high concentrations of ATP, seems to lose its sensitivity to FDP. This effect persists until ATP molecules are present in excess. In vitro incubation of deficient PK with ATPase resulted in increased PK activity as well as in recovery of its sensitivity to the stimulating effect of FDP. The same effects were obtained in vivo by administering magnesium levulinate intravenously to CNSHA patients with PK deficiency. This may indicate that magnesium ions stimulate deficient ATPase activity and lead to diminution of ATP as a negative effector for other regulatory enzymes.     

Procalcitonin as a diagnostic marker in differentiating parapneumonic effusion from tuberculous pleurisy or malignant effusion

Objectives

Differential diagnosis of exudative pleural effusions can be difficult, despite the use of several biomarkers. Serum procalcitonin (s-PCT) is a well-known biomarker for systemic bacterial infections. However, the usefulness of pleural fluid procalcitonin (pf-PCT) in clinical practice has not been established. This study evaluated the usefulness of PCT measurements in differentiating parapneumonic effusion (PPE) from tuberculous (TB) pleurisy or malignant effusion.

Design and methods

Ninety eight adult patients diagnosed with exudative pleural effusion were enrolled and allocated into the PPE group (n = 32), TB pleurisy group (n = 40), or malignant effusion group (n = 26). Both s-PCT and pf-PCT concentrations were measured at admission using an immunoluminometric assay.

Results

Both s-PCT and pf-PCT were significantly increased in the PPE group compared with the TB pleurisy or malignant effusion groups (p < 0.001). The optimal cut-off value for s-PCT in the diagnosis of PPE was 0.18 ng/mL (sensitivity 83.3%, specificity 81.0%). The pf-PCT cut-off value was 0.16 ng/mL (sensitivity 81.5%, specificity 72.1%). Serum PCT exhibited better diagnostic accuracy than pf-PCT, with areas under the receiver operating characteristic curves of 0.842 for s-PCT and 0.784 for pf-PCT (p = 0.015). In addition, s-PCT and pf-PCT showed better diagnostic accuracy than serum C-reactive protein (p = 0.005 and p = 0.023, respectively).

Conclusions

Measurement of s-PCT and pf-PCT is useful in differentiating PPE from TB pleurisy and malignant effusion. Both s-PCT and pf-PCT may be useful biomarkers in the differential diagnosis of exudative pleural effusions.     

A Thrombelastograph whole blood assay for clinical monitoring of NSAID-insensitive transcellular platelet activation by arachidonic acid

Optical platelet aggregation (OPA) with platelet-rich plasma (PRP) was compared with a Thrombelastograph (TEG) whole blood assay for monitoring arachidonic acid (AA)-induced platelet activation. Assays were performed on 47 interventional cardiology and 24 general surgery patients receiving aspirin therapy for cardiovascular disease, as well as 48 volunteers asked to take nonsteroidal anti-inflammatory drugs (NSAIDs) or 12 volunteers on chronic NSAID therapy unrelated to diagnosed cardiovascular disease. Whole blood TEG monitoring of NSAID inhibition detected NSAID-insensitive AA activation of platelets in a significantly higher number of cardiology (23%) and surgery (25%) patients and normal volunteers on chronic NSAID (25%) therapy relative to normal subjects not on chronic NSAID therapy (0%). Whole blood NSAID insensitivity was observed with cyclooxygenase-I inhibitors, such as aspirin and ibuprofen; was not affected by Celebrex, a cyclooxygenase-II inhibitor; but was completely inhibited by thromboxane-receptor antagonists. This was not due to platelet NSAID insensitivity, because complete inhibition of AA-activation responses in PRP was observed with either TEG or OPA assays. We confirmed that thromboxane B(2) formation in PRP from NSAID-insensitive subjects was completely inhibited by NSAIDs. However, significant amounts were formed in whole blood from NSAID-insensitive subjects, but not in whole blood from NSAID-sensitive subjects. Thromboxane formation after AA addition was not found in washed blood cells with 90% reduced platelet counts or in leukocyte-rich buffy coat fractions, but could be restored by addition of PRP. NSAID-insensitive activation was inhibited by nordihydroguaiaretic acid, with an IC(50) of 30 micromol, implicating 12- and/or 15-lipoxygenases in this transcellular pathway.     

Evaluation of a new PCR assay with competitive internal control sequence for blood donor screening

BACKGROUND: High-throughput nucleic acid testing for transfusion-relevant viruses by PCR requires contamination-proof methods with high sensitivity and validity. A new PCR reagent kit (TaqMan, PE BioSystems) reduces the risk of carry-over contamination by eliminating post-PCR processing. STUDY DESIGN AND METHODS: Oligonucleotide design was done with software specialized for designing the assays' (TaqMan) primers and probes. A template-derived competitive internal control sequence designed through site-directed mutagenesis was used to reveal failures in amplification. Assay sensitivity was determined for single-donor and single-patient testing and by spiking sample mini-pools. Three seroconversion panels were tested. RESULTS: Sensitivity is high, reaching 300 HBV genomes per mL of single-patient material on direct testing. A detection limit of 1000 HBV genome equivalents per mL of donor plasma is achieved for 96 pooled samples. The window period for HBV infection was reduced by 17, 10, and 63 days from that for HBsAg screening in three seroconverting donors. CONCLUSION: The assay provides sufficient sensitivity to be superior to HBsAg screening in transfusion medicine and will be useful in clinical laboratories because of its ease of handling.     

In vivo and in vitro characteristics of double units of RBCs collected by apheresis with a single in-line WBC-reduction filter

BACKGROUND: A novel apheresis procedure for a blood separator (MCS+, Haemonetics) enables the collection of 2 WBC-reduced RBC units in a single donation by using one disposable set with one in-line WBC-reduction filter (RC2H, Pall Corp.). The objective of this study was to evaluate the filtration performance in connection with different prefiltration RBC storage conditions and with the in vitro and in vivo storage quality of the filtered units. STUDY DESIGN AND METHODS: Sixty-six 2-unit RBC collection and gravity-filtration procedures were completed at three sites, resulting in 132 RBC units. Filtration of the double RBC units was performed at room temperature (RT) within 8 hours of collection (n = 36) and under refrigeration (1-6 degrees C) for up to 24 hours (n = 10) and 72 hours (n = 20) before filtration. RBC quality was compared to that of nonfiltered apheresis RBC units (n = 10). RESULTS: Median filtration time was 6.5 and 14 minutes for units stored at RT and under refrigeration, respectively. All 132 RBC units had residual WBC counts <0.4 x 10(6). The refrigerated units showed a greater mean log reduction in WBCs: 5.06 +/- 0.16 (24 hour) and 4.74 +/- 0.48 (72 hour), respectively, than did RT units: 4.47 +/- 0.28 (p<0.05). RBC loss was less than 12 percent in all cases (mean, 7.8 +/- 1.8%). Minimal differences in volume were observed between the paired RBC units. In vitro RBC storage characteristics of the filtered units were as expected and similar to those of the nonfiltered units. For RBC units held at RT (n = 24), the mean in vivo 24-hour recovery was 81.8 +/- 8.4 percent (double-label). CONCLUSION: Satisfactory filter performance in terms of WBC removal and RBC loss was observed with all 66 procedures, irrespective of storage conditions before filtration.     

Identification of Yersinia-infected blood donors by anti-Yop IgA immunoassay

BACKGROUND: From 1991 through 1996, nine transfusion-related cases of septicemia and endotoxemia occurred in New Zealand, a rate approximately 80 times that in the United States. Eight cases involved the transfusion of Yersinia enterocolitica-infected blood and one involved Serratia liquefaciens-infected blood. Six of the recipients died. Donor exclusion by recent gastrointestinal illness failed to prevent the four most recent such infections, and it has led to an estimated 3- to 5-percent rate of donor deferral. STUDY DESIGN AND METHODS: An antigen preparation containing the released proteins (Yops) of Y. enterocolitica was used to establish an EIA to detect IgA directed against these proteins in donated blood. The assay was tested with serum from donors in transfusion-related endotoxemia cases, subjects who were stool culture-positive for Y. enterocolitica, and 495 healthy volunteer blood donors. RESULTS: The assay detected anti-Yop IgA in the donors of all 6 infected units tested. Ninety-six percent of culture-positive subjects tested positive, whereas there was 70-percent positivity with a commercial immunoassay based on lipopolysaccharide. Five percent of random donors tested positive; only one of these had Y. enterocolitica present in a stool sample, and none were bacteremic. CONCLUSION: The anti-Yop immunoassay used in this study could be applied to reduce the risk of posttransfusion endotoxic shock caused by Y. enterocolitica.     

Development of a strategic process using checklists to facilitate team preparation and improve communication during neonatal resuscitation

Background

To improve our neonatal resuscitations we review video recordings of actual high-risk deliveries as an ongoing quality review process. In order to help identify and review errors that occurred during resuscitation we educated our resuscitation teams using crew resource management and in March 2009 developed a checklist to be used for potentially high-risk resuscitations.

Objective

To describe our experience using checklists as an essential component of the actual resuscitation of potentially high-risk infants.

Design/methods

The checklist includes pre- and debrief components, along with duty-specific sub-lists (MD, RT, RN). The debrief is conducted upon completion of the resuscitation and addresses what was done well, what was not done well, and how it could have been improved. We reviewed all available checklists from March 2009 to November 2011 (n = 260). We then performed a second review to determine if experience has changed the leaders perception of how resuscitation was being performed from November 2011 to May 2012 (n = 185).

Results

We reviewed 445 completed checklists with quality assurance video review. During the initial cohort the most commonly described problems were: communication (n = 58), equipment preparation and use (n = 56), inappropriate decisions (n = 87), leadership (n = 56), and procedures (n = 25). The number of debriefs where communication was identified as a problem decreased from 23% in the first time period to 4% (p < 0.001) in the latter.

Conclusions

The use of checklists during neonatal resuscitation was helpful in improving overall communication, and allowed for rapid identification of issues that need to be addressed by institutional leaders. There needs to be further evaluation of the utility and benefit of checklists for neonatal resuscitation. Based on our past and present experience we encourage the use of checklists for neonatal resuscitation teams.     

Some glycolytic enzymes in normal cerebrospinal fluid, brain tissue and blood plasma of infants.

The activities of several glycolytic enzymes (hexokinase, phosphofructokinase, pyruvate kinase, lactate dehydrogenase) as well as glycerol-1-phosphate dehydrogenase and (Mg2+)ATPase in normal cerebrospinal fluid (CSF) and blood plasma samples, from 12 healthy infants, aged 2-18 months, and in supernatants from brain tissue slices, taken during neurosurgical operations from infants of the same range of age were estimated. The values obtained confirm the high activity of the above enzymes found in animal brains, and indicate an independence of these activities in blood plasma and CSF. The origin of the activities of the investigated enzymes in CSF seems to be mainly, if not, exclusively, from brain tissue. This might be useful for detection of brain tissue damage as was earlier proven with LDH activity in CSF.     

Ethyl pyruvate ameliorates acute alcohol-induced liver injury and inflammation in mice

Ethyl pyruvate dissolved in a calcium-containing balanced salt solution--Ringer's ethyl pyruvate solution (REPS)--ameliorates ileal mucosal hyperpermeability and decreases the expression of several proinflammatory genes when it is used instead of Ringer's lactate solution (RLS) to resuscitate mice from hemorrhagic shock. Herein, we sought to determine whether delayed treatment with REPS would be beneficial in a murine model of acute alcoholic liver injury associated with binge drinking. Mice were gavaged with 3 doses of ethanol (5 g/kg each dose) over a 12-hour period and then randomized to treatment with 3 intraperitoneal doses of REPS or RLS over 12 hours. Compared with sham-treated controls not subjected to alcohol intoxication, RLS-treated mice demonstrated histologic evidence of fatty change and piecemeal necrosis of hepatocytes in the liver, as well as a significant increase in the plasma concentration of alanine aminotransferase. Biochemical changes induced by alcohol administration included increased hepatic lipid peroxidation, nuclear factor-kappaB activation, and tumor necrosis factor-alpha messenger RNA expression. All of these alcohol-induced effects were ameliorated by treatment with REPS instead of RLS. These data support the view that treatment with REPS ameliorates the hepatic inflammatory response and decreases hepatocellular injury in mice subjected to acute alcohol intoxication.     

抗乙醇脱氢酶抗体ELISA法的建立及其对自身免疫性肝炎诊断的价值

目的 建立血清抗乙醇脱氢酶(alcohol dehydrogenase,ADH)抗体ELISA法,并评价抗.ADH在诊断自身免疫性肝炎(AIH)中的价值.方法 用免疫印迹试验对酵母ADH与人血清抗.ADH之间的反应性进行验证.用酵母ADH建立检测血清抗-ADH的ELISA法.以67例AIH、94例原发性胆汁性肝硬化(PBC)、199例慢性乙型肝炎(CHB)、132例慢性丙型肝炎(CHC)、24例酒精性肝病(ALD)和99例结缔组织病(CTD)患者及31名健康对照者为研究对象,对其血清中的抗-ADH进行检测并统计其阳性率,阳性率的比较用χ2检验.结果 建立了一种检测人血清抗-ADH的ELISA法,并确定了最佳反应条件;免疫印迹试验证实酵母ADH与人血清抗-ADH有良好反应性.AIH患者血清抗-ADH阳性率为59.7%(40/67),高于健康对照组(0,χ2=31.271,P<0.05)、PBC组(6.4%,χ2=54.492,P<0.05)、CHB组(14.1%,χ2=54.848,P<0.05)、CHC组(21.2%,χ2=29.269,P<0.05)、ALD组(25.0%,χ2=8.512,P<0.05)和CTD组(43.4%,χ2=4.229.P<0.05).结论 AIH患者血清中抗-ADH阳性率高于其他肝病和某些自身免疫性疾病患者,可能对AIH有一定辅助诊断价值.     

干滤纸血片制备环境的理化因素对实验结果的影响

目的观察新生儿疾病筛查干滤纸血片(dried blood spots)制备环境中显著影响实验结果的理化因素。方法研究组1:收集正常标本60例、阳性标本120例,于对照条件及10种特定环境下制备干滤纸血片。研究组2:另收集正常标本30例、阳性标本80例,于对照条件及7种甲醛浓度环境下制备干滤纸血片。用荧光法或时间分辨荧光免疫分析法检测标本中苯丙氨酸(Phe)、葡萄糖-6-磷酸脱氢酶(G6PD)、促甲状腺激素(TSH)、17α-羟孕酮(17α-OHP)水平。用SPSS 22.0软件进行统计学分析。结果 10种环境下制备的干滤纸血片Phe检测结果与对照组差异无统计学意义(P0.05),甲醛敏感阈为4.62~6.95 ppm/18 h;37℃烘箱、潮湿、紫外线照射、新装修环境、乙醇、冰醋酸、甲醛等环境下制备的干滤纸血片G6PD检测结果低于对照组(P0.05),甲醛敏感阈为0.30~0.38 ppm/4 h及0.21~0.24 ppm/18 h;潮湿、紫外线照射、甲醛环境下制备的干滤纸血片TSH检测结果低于对照组(P0.05),甲醛敏感阈为0.32~0.52 ppm/4 h及0.38~0.45 ppm/18 h;潮湿、紫外线照射、甲醛环境下制备的干滤纸血片17α-OHP检测结果低于对照组(P0.05),甲醛敏感阈为4.37~4.62 ppm/4 h及0.38~0.45 ppm/18 h。冷风快速吹干与2~8℃冷库环境下制备干滤纸血片4项检测结果与对照组差异均无统计学意义(P均0.05)。结论干滤纸血片制备环境的理化因素与新生儿疾病筛查的准确性密切相关,甲醛、乙醇、冰醋酸、紫外线照射、高温、潮湿及装修污染等是干滤纸血片制备环境的必要管控因素;冷风快速吹干与2~8℃冷库过夜可作为新生儿筛查干滤纸血片制备的备选方法。     

血清游离脂肪酸酶法测定的方法学评价及生物学变异研究

目的评价血清游离脂肪酸(FFA)酶学比色法(简称酶法)的精密度和正确度,并且研究血清FFA个体间和个体内生物学变异。方法采用美国临床和实验室标准化协会(CLSI)EP5-A2和EP15-A文件评价酶法测定血清FFA的精密度和正确度。生物学变异的研究对象为13名健康志愿者,在6周时间内每2周测定1次血清FFA浓度,利用SAS9.1软件中MIXED分析过程计算个体间生物学变异和个体内生物学变异。结果精密度实验样品的血清FFA浓度总均数为0.796 mmol/L,批内、批间、日间和室内不精密度分别为2.15%、3.44%、3.67%和5.46%。测定3个室间质评样品的百分比偏差分别为24.20%、-0.90%、-1.50%。血清FFA个体间和个体内生物学变异分别为8.43%、19.36%。结论酶法测定血清FFA的精密度和正确度能满足相关实验室质量控制要求。血清FFA的个体间和个体内生物学变异可为制定实验室质量规范和临床课题的科研设计提供参考依据。