Influence of therapeutic plasma exchange treatment on short-term mortality of critically ill adult patients with sepsis-induced organ dysfunction: a systematic review and meta-analysis.

INTRODUCTION: The impact of therapeutic plasma exchange (TPE) on short-term mortality in adult patients with sepsis-induced organ dysfunction remains uncertain. The objective of the study is to assess the effect of adjunct TPE in this setting through a comprehensive literature review. METHODS: The National Library of Medicine's Medline, Ovid (Embase), the Cochrane Library database and clinicaltrial.gov from January 01, 1966, until October 01, 2022, were searched for terms: therapeutic plasma exchange, plasmapheresis, sepsis, and septic shock. We reviewed, selected and extracted data from relevant randomized clinical trials (RCTs) and matched cohort studies (MCSs) comparing short-term mortality in critically ill adult septic patients treated with standard therapy versus those receiving adjunct TPE. Risk of bias was assessed in the RCTs using Cochrane Collaboration tool and in MCSs using ROBINS-I tool. Summary statistics, risk ratios (RRs), and confidence intervals (CIs) were calculated using random effects model. RESULTS: This systematic review included 937 adult critically ill septic patients from five RCTs (n = 367) and fifteen MCSs (n = 570). Of these total, 543 received treatment with TPE in addition to standard care. The meta-analysis includes all five RCTs and only six MCSs (n = 627). The adjunct TPE treatment (n = 300) showed a significant reduction in short-term mortality (RR 0.59, 95% CI 0.47-0.74, I2 3%) compared to standard therapy alone (n = 327). The systematic review of all 20 trials revealed that adding TPE to the standard therapy of critically ill septic patients resulted in faster clinical and/or laboratory recovery. CONCLUSIONS: Our comprehensive and up-to-date review demonstrates that adjunct TPE may provide potential survival benefits when compared to standard care for critically ill adult patients with sepsis-induced organ dysfunction. While results of this meta-analysis are encouraging, large well-designed randomized trials are required to identify the optimal patient population and TPE procedure characteristics prior to widespread adoption into practice.

Baseline Serum Prostate-specific Antigen Value Predicts the Risk of Subsequent Prostate Cancer Death-Results from the Norwegian Prostate Cancer Consortium.

BACKGROUND: Prostate-specific antigen (PSA) levels in midlife are strongly associated with the long-term risk of lethal prostate cancer in cohorts not subject to screening. This is the first study evaluating the association between PSA levels drawn as part of routine medical care in the Norwegian population and prostate cancer incidence and mortality. OBJECTIVE: To determine the association between midlife PSA levels <4.0 ng/ml, drawn as part of routine medical care, and long-term risk of prostate cancer death. DESIGN, SETTING, AND PARTICIPANTS: The Norwegian Prostate Cancer Consortium collected >8 million PSA results from >1 million Norwegian males ≥40 yr of age. We studied 176 099 men (predefined age strata: 40-54 and 55-69 yr) without a prior prostate cancer diagnosis who had a nonelevated baseline PSA level (<4.0 ng/ml) between January 1, 1995 and December 31, 2005. INTERVENTION: Baseline PSA. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: We assessed the 16-yr risk of prostate cancer mortality. We calculated the discrimination (C-index) between predefined PSA strata (<0.5, 0.5-0.9, 1.0-1.9, 2.0-2.9, and 3.0-3.9 ng/ml) and subsequent prostate cancer death. Survival curves were plotted using the Kaplan-Meier method. RESULTS AND LIMITATIONS: The median follow-up time of men who did not get prostate cancer was 17.9 yr. Overall, 84% of men had a baseline PSA level of <2.0 ng/ml and 1346 men died from prostate cancer, with 712 deaths (53%) occurring in the 16% of men with the highest baseline PSA of 2.0-3.9 ng/ml. Baseline PSA levels were associated with prostate cancer mortality (C-index 0.72 for both age groups, 40-54 and 55-69 yr). The fact that the reason for any given PSA measurement remains unknown represents a limitation. CONCLUSIONS: We replicated prior studies that baseline PSA at age 40-69 yr can be used to stratify a man's risk of dying from prostate cancer within the next 15-20 yr. PATIENT SUMMARY: A prostate-specific antigen level obtained as part of routine medical care is strongly associated with a man's risk of dying from prostate cancer in the next two decades.

Rapid diagnosis and reduced workload for urinary tract infection using flowcytometry combined with direct antibiotic susceptibility testing.

BACKGROUND: We evaluated if flowcytometry, using Sysmex UF-5000, could improve diagnosis of urinary tract infections by rapid identification of culture negative and contaminated samples prior to culture plating, thus reducing culture plating workload and response time. We also evaluated if it is possible to reduce the response time for antibiotic susceptibility profiles using the bacteria information flag on Sysmex UF-5000 to differentiate between Gram positive and negative bacteria, followed by direct Antibiotic Susceptibility Testing (dAST) on the positive urine samples. METHODS: One thousand urine samples were analyzed for bacteria, white blood cells and squamous cells by flowcytometry before culture plating. Results from flowcytometric analysis at different cut-off values were compared to results of culture plating. We evaluated dAST on 100 urine samples that were analyzed as positive by flowcytometry, containing either Gram positive or Gram negative bacteria. RESULTS: Using a cut-off value with bacterial count ≥100.000/mL and WBCs ≥10/µL, flowcytometry predicted 42,1% of samples with non-significant growth. We found that most contaminated samples contain few squamous cells. For 52/56 positive samples containing Gram negative bacteria dAST was identical to routine testing. Overall, there was concordance in 555/560 tested antibiotic combinations. CONCLUSION: Flowcytometry offers advantages for diagnosis of urinary tract infections. Screening for negative urine samples on the day of arrival reduces culture plating and workload, and results in shorter response time for the negative samples. The bacteria information flag predicts positive samples containing Gram negative bacteria for dAST with high accuracy, thus Antibiotic Susceptibility Profile can be reported the day after arrival. For the positive samples containing Gram negative bacteria the concordance was very good between dAST and Antibiotic Susceptibility Testing in routine. For positive samples containing Gram positive bacteria the results were not convincing. We did not find any correlation between epithelial cells and contamination.

Lowered reference limits for hCG improve follow-up of patients with hCG-producing tumors.

BACKGROUND: Human Chorionic Gonadotropin (hCG) is produced by germ cell tumors, but can also be elevated in benign conditions such as primary hypogonadism, where hCG is produced by the pituitary gland. In our experience, the reference limits for hCG (Elecsys hCG+ß-assay, Roche Diagnostics), were unnecessarily high and did not reflect levels encountered in clinical practice. We wanted to establish new reference limits to increase the clinical utility of the hCG-assay. METHODS: We analysed hCG in serum samples from a healthy adult population and in a cohort of testicular cancer survivors. The gonadotropins LH and FSH were measured in the cohort and in a selection of the reference population to assess gonadal function. RESULTS: We found low hCG levels for all men and women <45years (97.5 percentiles 0.1 and 0.2IU/L, respectively) from the healthy population (n=795) having normal FSH and LH. Due to assay limitations, we suggest a common reference limit of <0.3IU/L. For the age group ≥45, the 97.5 percentiles in the healthy population were 0.5IU/L for men and 6.0IU/L for women. In all subjects from both the reference population and the cohort (n=732), hCG levels exceeding the reference limit could be fully explained by reduced gonadal function indicated by elevated LH and FSH levels. CONCLUSION: The Elecsys hCG+ß-assay should have lower reference limits than recommended by the manufacturer, with important implications for tumor follow-up. Elevated hCG is rare with intact gonadal function, both in a normal population and among survivors of testicular cancer, and should lead to further investigations when encountered in clinical practice.

Interference of common haemoglobin variants with the Tosoh G7 standard mode HbA1c method.

BACKGROUND: HbA1c methods may be prone to interference by the presence of haemoglobin variants. In contrast to the variant mode of the HbA1c method on the Tosoh G7 instrument, the literature lacks investigations of haemoglobin variant interference with the standard mode. The current study sought to investigate whether different haemoglobin variants interfere with the Tosoh G7 standard mode HbA1c method, and whether present haemoglobin variants are identifiable on respective chromatograms. METHODS: Samples routinely analyzed for HbA1c and suspected of having haemoglobin variants (N = 103) were included. HbA1c was measured on a Tosoh G7 in standard mode (Tosoh Corporation, Japan), and on the DCA Vantage (Siemens, Germany). Haemoglobin variants were identified using the VARIANT(™)ß-Thalassemia Short Program (Bio-Rad Laboratories, Hercules, CA, USA) and by DNA sequencing. RESULTS: The Tosoh G7 in standard mode measured significantly lower HbA1c results (between 1.0 and 2.5 percentage points absolute bias corresponding to between 11 and 27 mmol/mol, p < 0.001) in samples in which common haemoglobin variants (HbS, HbC, HbD or HbE) were present (n = 61). No significant difference in HbA1c (0.04 percentage points, p = 0.74) was found between Tosoh G7 standard mode and DCA Vantage in samples in which haemoglobin variants were absent (n = 36). In contrast to HbS and HbD, HbE and HbC trait could be identified on respective chromatograms. CONCLUSION: The presence of common haemoglobin variants results in falsely low HbA1c measurements on the Tosoh G7 in standard mode. HbS and HbD trait are not identifiable on respective haemoglobin chromatograms.

Longitudinal serum testosterone, luteinizing hormone, and follicle-stimulating hormone levels in a population-based sample of long-term testicular cancer survivors.

PURPOSE: To assess longitudinal long-term alterations of testosterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) in testicular cancer survivors (TCSs). PATIENTS AND METHODS: In all, 307 TCSs treated from 1980 to 1994 provided blood samples after orchiectomy but before further treatment, at Survey I (SI; 1998-2002), and Survey II (SII; 2007-2008). Levels of sex hormones were categorized according to quartiles and reference range (2.5 and 97.5 percentiles) of 599 controls for each decadal age group. TCSs were categorized according to treatment: surgery, radiotherapy (RT), or chemotherapy (CT). The risk of higher (LH) or lower (testosterone) levels was assessed with χ(2) test (FSH) or ordinal logistic regression analysis and expressed as odds ratios (ORs) with 95% CIs. RESULTS: Risk of lower testosterone and higher LH and FSH levels was significantly increased for TCSs at all time points after RT or CT. At SII, ORs were 3.3 (95% CI, 2.3 to 4.7) for lower testosterone categories and 5.2 (95% CI, 3.5 to 7.9) for RT and CT. ORs for increased LH and FSH were 4.4 (95% CI, 3.1 to 6.5) and 18.9 (95% CI, 11.0 to 32.6) for RT, respectively, and 3.6 (95% CI, 2.4 to 5.3) and 14.2 (95% CI, 8.3 to 24.4) for CT, respectively. The cumulative platinum dose was significantly associated with risk of higher LH levels at both surveys and higher FSH at SI. In total, half the TCSs had at least one of three sex hormone levels outside the reference range at SII. CONCLUSION: Long-term TCSs are at risk of premature hormonal aging. Our findings may pertain to cancer survivors in general, underlining the importance of extended follow-up.

Belief is only half the truth--or why screening for heterophilic antibody interference in certain assays makes double sense.

BACKGROUND: Interference in immunoassays may cause both false-negative and false-positive results. It may be detected using a number of affirmative tests such as reanalysis of certain samples using different assay platforms with known bias, after the addition of blocker antibodies, or assessment of linearity and parallelism following serial doubling dilutions. One should look for interference where it is likely and has high medical impact. Probabilistic Bayesian reasoning is a statistical tool to identify samples where interference is most likely. But when looking for interference where it is likely, do we find it where it has the largest population health consequences? METHODS: We used information theory to quantify the effect of assay interference by calculating the Shannon information content (using logarithms with base 2). We then obtained lower bounds of the population health consequences of a particular test and combined these expressions to get lower bounds of the population health consequences of interference. RESULTS AND CONCLUSION: We suggest that assays having a low frequency of true positives should be the primary target of retesting because: (i) assays with a low frequency of true positives exhibit a high likelihood of interference and (ii) the population health consequences of false-positive results are generally higher for assays with a low frequency of true positives. Finally, we give a worked example having a realistic frequency of interference and test costs. In some immunoassays (e.g., tumour markers), adding a blocker to all tests can be a more cost-efficient mean than retesting positive samples.

Human epididymis protein 4 reference limits and natural variation in a Nordic reference population.

The objectives of this study are to establish reference limits for human epididymis protein 4, HE4, and investigate factors influencing HE4 levels in healthy subjects. HE4 was measured in 1,591 samples from the Nordic Reference Interval Project Bio-bank and Database biobank, using the manual HE4 EIA (Fujirebio) for 802 samples and the Architect HE4 (Abbott) for 792 samples. Reference limits were calculated using the statistical software R. The influence of donor characteristics such as age, sex, body mass index, smoking habits, and creatinine on HE4 levels was investigated using a multivariate model. The study showed that age is the main determinant of HE4 in healthy subjects, corresponding to 2% higher HE4 levels at 30 years (compared to 20 years), 9% at 40 years, 20% at 50 years, 37% at 60 years, 63% at 70 years, and 101% at 80 years. HE4 levels are 29% higher in smokers than in nonsmokers. In conclusion, HE4 levels in healthy subjects are associated with age and smoking status. Age-dependent reference limits are suggested.

Heterophilic antibody interference in commercial immunoassays; a screening study using paired native and pre-blocked sera.

BACKGROUND: Heterophilic antibodies are still an important source of interference in immunoassays. We have conducted a screening study for interference in a panel of commercially available assays using two sera known to contain high titer Fc-reactive heterophilic antibodies. METHODS: The sera were distributed to laboratories participating in the Nordic External Quality Assessment cooperation (EQANord). Duplicate samples pre-blocked with aggregated murine monoclonal MAK33 were also supplied. Discrepancies (>50%) between the results for native and blocked samples were used to classify the tested assays as susceptible to interference. A total of 170 different assay kits covering 91 analytes were tested. RESULTS: We found that 21 assays, covering 19 different analytes, were susceptible to interference from the heterophilic antibodies in the two sera. Many of these are clinically and commercially important assays. Some of the false results were grossly elevated and could have been detrimental to patient care in a clinical setting. CONCLUSIONS: Heterophilic antibodies with Fc-reactivity remain a threat. A more widespread use of antibody fragments and aggregated immunoglobulin could potentially improve the heterophilic antibody resistance of assays intended for clinical use.

[The Swedish Chlamydia mutant nvC trachomatis in Norway]. / Den svenske chlamydiavarianten nvC trachomatis i Norge.

BACKGROUND: A mutant Chlamydia trachomatis variant (nvC trachomatis) has made it more difficult to diagnose chlamydia in Sweden. The proportion of nvC trachomatis has varied between Swedish counties (25-80 %) in the period 2006-07. Our goal has been to monitor nvC trachomatis among our patients from January 2007 and up to July 2008. MATERIAL AND METHODS: In this time period, all C trachomatis samples at Fürst Medical Laboratory, Norway were analyzed twice. Cobas TaqMan 48 (Roche Diagnostics) was used to detect C trachomatis in isolated DNA and real-time PCR methods developed by us were used to both detect and verify nvC trachomatis. RESULTS: 61 patients of 23 726 patients were identified as carriers of nvC trachomatis. The proportion of C trachomatis carriers who were positive for nvC trachomatis increased from 1.0 % in the first quarter of 2007 to 3.2 % in the second quarter of 2008. INTERPRETATION: Our results show a slow but steady increase in the proportion of nvC trachomatis positive tests. As compared to previous rates reported in Sweden (25-80 %), the occurrence of nvC trachomatis in our data is low. The epidemiology of this chlamydia mutant contributes to the understanding of mechanisms for spread of sexually transmitted infections and emphasize that you only find what you are looking for.

Reference intervals for serum testosterone, SHBG, LH and FSH in males from the NORIP project.

Reference intervals were calculated for male testosterone, SHBG, FSH and LH in serum from 599 individuals in the NORIP study. At 30 years of age, reference limits were calculated to 10.4-32.6 nmol/L testosterone, 13.5-57.4 nmol/L SHBG, 1.93-9.7 IU/L LH and 1.5-10.3 IU/L FSH, at 50 years, 9.3-31.3 nmol/L (testosterone), 18.4-75.6 nmol/L (SHBG), 2.01-10.4 IU/L (LH) and 2.04-12.4 IU/L (FSH), and at 70 years 8.6 to 30.7 nmol/L (testosterone), 27.8-101 nmol/L (SHBG), 2.22-11.2 IU/L (LH) and 2.71-14.2 IU/L (FSH). All age-+related changes were statistically significant. Reference intervals were also calculated for indices derived from testosterone, SHBG and albumin. Free androgen index, simply the ratio between testosterone and SHBG, returned results differing from the other elaborate indices, and the study thus favors use of a more elaborate index such as calculated free testosterone (CFT).

Progastrin-releasing peptide: stability in plasma/serum and upper reference limit.

BACKGROUND: Progastrin-releasing peptide (proGRP) is a promising tumor marker for small cell lung cancer (SCLC). Here we study the stability of proGRP in serum and plasma, as well as proGRP levels in healthy individuals, to provide a framework for clinical studies. METHODS: Serum, with and without protease inhibitors, and plasma from SCLC patients and healthy individuals were assayed for proGRP immediately after collection and following various storage conditions. RESULTS: No degradation was observed in serum or plasma after storage for 4 weeks at -30 degrees C. Serum proGRP levels were stable for up to 3 days at 4 degrees C, but decreased at room temperature. Addition of protease inhibitors to patient serum did not markedly improve stability. In EDTA plasma, proGRP concentrations increased upon storage in some samples at room temperature and 4 degrees C. When assayed immediately after collection, no significant variations in proGRP concentrations were observed between serum and EDTA plasma (n = 171). A 97.5-percentile reference limit of 58.9 ng/l was calculated from data from 806 individuals. However, proGRP levels were significantly correlated with age, sex, creatinine concentrations, body mass index and smoking. CONCLUSION: Serum is the preferred material for measuring proGRP, provided it is stored at 4 degrees C and assayed within 3 days.

Reference intervals for carcinoembryonic antigen (CEA), CA125, MUC1, Alfa-foeto-protein (AFP), neuron-specific enolase (NSE) and CA19.9 from the NORIP study.

OBJECTIVE: Adhering to current IFCC recommendations, we calculated upper 97.5 % reference limits for serum tumor markers. MATERIAL AND METHODS: Serum samples from 498 healthy individuals from the Nordic reference interval project (NORIP) were investigated for carcinoembryonic antigen (CEA), CA125 and MUC1 (episialin, CA15.3) using in-house immunofluorometric assays and, for alpha-foetoprotein (AFP), a PerkinElmer Life Sciences assay, neuron-specific enolase (NSE) using an in-house immunoradiometric assay and CA19.9 using a Beckman Access assay. All assays participate in external quality assessment programs. RESULTS: CEA concentrations increased with age and smoking. Upper reference limits for non-smokers were 3.59 microg/L at 50 years and 4.12 microg/L at 70 years. CA125 concentrations were age-independent and the upper reference limit was 35.8 kU/L. MUC1 increased with age and body mass index (BMI). Upper reference limits were 31.7 kU/L at 40 years and BMI 24, 37.5 kU/L at 70 years and BMI 24, and 33.7 kU/L at 40 years and BMI 30. AFP increases with age, and the upper reference limits were 3.82 kU/L at 20 years and 8.70 kU/L at 60 years. An upper reference limit for NSE was 8.91 microg/L in non-smokers; smokers exhibited significantly lower levels. The upper reference limit for individuals expressing CA19.9 was 28.3 kU/L. CONCLUSIONS: For AFP, CA125 and CA19.9, the reference levels obtained were close to previously reported reference ranges. Smoking and age were confirmed as covariates for CEA. The associations between MUC1 with age and BMI and between NSE and smoking have not been reported previously.

Automated time-resolved immunofluorometric assay for progastrin-releasing peptide.

BACKGROUND: Small cell lung cancer accounts for approximately 20% of new cases of lung cancer, and advanced disease is prevalent at the time of diagnosis. Neuron-specific enolase (NSE) has been the primary tumor marker in small cell lung cancer but it has relatively low sensitivity in early-stage disease. Progastrin-releasing peptide (proGRP) is a promising alternative or complementary marker for NSE. We have previously described a time-resolved immunofluorometric assay (TR-IFMA) for proGRP that lacked the necessary sensitivity and robustness for use in the routine clinical laboratory. Herein we describe the development of an improved assay using a novel monoclonal antibody pair. METHODS: Mice were immunized with different conjugated proGRP peptides, including residues 31-98, 1-98, and preproGRP(-23-125). Pair combinations of the resulting monoclonal antibodies (mAb) were tested. The improved TR-IFMA was compared with the only other available proGRP assay, the proGRP ELISA (IBL). RESULTS: A panel of 12 high-affinity mAbs was produced. The best assay combination was between our original E146 mAb as solid-phase antibody and the new mAb M16 as tracer. The new TR-IFMA had a linear dose-response curve, a wide dynamic range (13-13 500 ng/L), and a limit of detection of 2.8 ng/L. Total CV was <5.6% over the whole measuring range. Bland-Altman difference analysis indicated a significant positive bias between the IFMA and the ELISA. CONCLUSIONS: We describe a sensitive and robust mAb-based TR-IFMA for proGRP. The assay is fully automated and displays high quality performance.

Human heterophilic antibodies display specificity for murine IgG subclasses.

OBJECTIVES: The study investigated heterophilic antibodies: the human immunoglobulin classes involved and their specificity for different murine IgG subclasses. DESIGN AND METHODS: Using immunofluorometric assays for human IgA, IgM and IgG binding murine IgG1, we analyzed 173 samples displaying positive interference and 97 negative control samples from a previous study. We also set up assays for heterophilic antibody interference using Mabs from different murine IgG subclasses. Three Mabs each of murine IgG1, IgG2a and IgG2b subclasses, one murine IgG3 Mab and one rat Mab were used. RESULTS: Elevated levels of human murine IgG1-binding immunoglobulins of IgM class only were found in 40% of interference-positive samples, human IgG only in 1.7%, and human IgA only in 2.3% of the samples. Both elevated human IgG and IgM classes were found in 3.5% of the samples, IgA and IgM in 4.0%, and finally, all three immunoglobulin classes in 1.7% of the samples. Eighty percent of interference positive samples showed heterophilic assay interference for at least one murine IgG1 Mab, 35% for IgG2a, 66% for IgG2b, 52% for IgG3a and 17% for the rat Mab. CONCLUSIONS: Heterophilic antibody interference is mainly caused by IgM class human antibodies with a marked murine IgG subclass specificity. Combining assay antibodies from different murine IgG subclasses may reduce interference in immunoassays.

Use of an in vivo biotinylated single-chain antibody as capture reagent in an immunometric assay to decrease the incidence of interference from heterophilic antibodies.

BACKGROUND: Heterophilic antibodies are a common source of interference in immunometric assays. We tested the hypothesis that the incidence of such interference could be decreased by use of a recombinant in vivo-biotinylated single-chain antibody (scFv) as the capture reagent. METHODS: We established three assays for carcinoembryonic antigen (CEA) with the capture antibody either chemically biotinylated whole monoclonal T84.66 immunoglobulin, a corresponding F(ab')2 fragment, or a site-specifically biotinylated T84.66-derived single-chain antibody (scFv). Antibodies were attached to streptavidin-coated microplates. A common europium-labeled anti-CEA tracer monoclonal antibody was used. The F(ab')2 assay used a buffer that contained bovine immunoglobulin and aggregated irrelevant monoclonal antibody MAK33 as blocking agents. The whole T84.66 immunoglobulin and scFv assays were performed without addition of blocking agents. From a previous study of 11 261 sera, we tested 390 samples that had displayed heterophilic antibody interference and 179 samples that had not. RESULTS: After correction for bias and analytical variation [2.56 x SD (from the precision profile)], 383 samples displayed significantly different values (>1 microg/L) in the whole T84.66-based assay and the F(ab')2 assay. In contrast, only nine samples showed falsely high CEA concentrations in the scFv assay. After blocking agents were added to the assay buffer, eight of the nine samples displayed results equivalent to those of the F(ab')2 assay, and sample dilution produced equivalent results for the remaining sample. CONCLUSION: Their ability to be site-specifically biotinylated and their relative resistance to heterophilic antibody interference indicate that single-chain antibodies may be useful solid-phase reagents in immunometric assays.