A comparison between formol saline and Mirsky's fluid as fixatives for nematodes

In order to evaluate the fixing properties of Mirsky's fluid on nematodes, a comparison was made with formaldehyde. On two occasions, nematodes recovered from the abomasa of calves were fixed in each of three of the following fluids: 5% formol saline, 10% formol saline, 5% Mirsky's fluid and 10% Mirsky's fluid. Based on measurements of length and microscopical examination of over 800 nematodes on each occasion, the authors concluded that Mirsky's fluid conferred no advantages over 5% formol saline or 10% formol saline for fixing nematodes.     

Antibody responses to individual proteins of SARS coronavirus and their neutralization activities

A novel coronavirus, the severe acute respiratory syndrome (SARS) coronavirus (SARS-CoV), was identified as the causative agent of SARS. The profile of specific antibodies to individual proteins of the virus is critical to the development of vaccine and diagnostic tools. In this study, 13 recombinant proteins associated with four structural proteins (S, E, M and N) and five putative uncharacterized proteins (3a, 3b, 6, 7a and 9b) of the SARS-CoV were prepared and used for screening and monitoring their specific IgG antibodies in SARS patient sera by protein microarray. Antibodies to proteins S, 3a, N and 9b were detected in the sera from convalescent-phase SARS patients, whereas those to proteins E, M, 3b, 6 and 7a were undetected. In the detectable specific antibodies, anti-S and anti-N were dominant and could persist in the sera of SARS patients until week 30. Among the rabbit antisera to recombinant proteins S3, N, 3a and 9b, only anti-S3 serum showed significant neutralizing activity to the SARS-CoV infection in Vero E6 cells. The results suggest (1) that anti-S and anti-N antibodies are diagnostic markers and in particular that S3 is immunogenic and therefore is a good candidate as a subunit vaccine antigen; and (2) that, from a virus structure viewpoint, the presence in some human sera of antibodies reacting with two recombinant polypeptides, 3a and 9b, supports the hypothesis that they are synthesized during the virus cycle.     

Coexistence of hepatitis B surface antigen (HBs Ag) and anti-HBs antibodies in chronic hepatitis B virus carriers: influence of "a" determinant variants

In chronic hepatitis B (CHB), the persistence of hepatitis B surface antigen (HBs Ag) is sometimes associated with antibodies (Ab) to HBs (anti-HBs). To assess the hypothesis of the selection of HBs Ag immune escape variants in CHB patients, the variability of the HBV S gene was determined for patients persistently carrying both HBs Ag and anti-HBs antibodies and patients solely positive for HBs Ag. We selected 14 patients who presented both markers (group I) in several consecutive samples and 12 patients positive for HBs Ag only (group II). The HBs Ag-encoding gene was amplified and cloned, and at least 15 clones per patient were sequenced and analyzed. The number of residue changes within the S protein was 2.7 times more frequent for group I than for group II patients and occurred mostly in the "a" determinant of the major hydrophilic region (MHR), with 9.52 versus 2.43 changes per 100 residues (P = 0.009), respectively. Ten patients (71%) from group I, but only three (25%) from group II, presented at least two residue changes in the MHR. The most frequent changes in group I patients were located at positions s145, s129, s126, s144, and s123, as described for immune escape variants. In CHB patients, the coexistence of HBs Ag and anti-HBs Ab is associated with an increase of "a" determinant variability, suggesting a selection of HBV immune escape mutants during chronic carriage. The consequences of this selection process with regard to vaccine efficacy, diagnosis, and clinical evolution remain partially unknown.     

Cross-reactivity of antibody against SARS-coronavirus nucleocapsid protein with IL-11

Infection of SARS-associated coronavirus (SARS-CoV) induced a strong anti-nucleocapsid (anti-N) antibody response. However, the pathophysiological significance of the anti-N antibodies in SARS pathogenesis is largely unknown. To profile the anti-N antibodies, a phage-displayed scFv library was prepared from mice immunized with heat-inactivated SARS-CoV-infected Vero E6 cell lysate. Specific anti-N scFvs were isolated by panning against a recombinant nucleocapsid protein and reactivity was confirmed with phage-ELISA. Sequence analysis indicated that two of the isolated anti-N scFv clones were identical and displayed a high homology with an scFv specific for interleukin 11 (IL-11), an anti-inflammatory cytokine derived from bone marrow stroma cells. In a neutralization assay, IL-11-induced STAT 3 phosphorylation in rat intestinal epithelial IEC-18 cells was completely suppressed by the anti-N scFv clone L9N01.     

Prevalence of nontuberculous mycobacteria in water supplies of hemodialysis centers

Infection of hemodialysis patients with nontuberculous mycobacteria (NTM) has been associated with water used in reprocessing hemodialyzers. This study was conducted to determine the prevalence of NTM and other bacteria in water samples collected over a 13-week period from 115 randomly selected dialysis centers in the United States. Total viable counts were determined by membrane filter assays; increased recovery of NTM was obtained by dosing a portion of each water sample with 1% formaldehyde (HCHO) before filtering. NTM were widely distributed and occurred with a high frequency in water supplies in dialysis centers. NTM were detected in water from 95 centers (83%), and 50% of all samples examined contained NTM. The results of this study support recommendations to use 4% HCHO or a chemical germicidal equivalent for disinfecting dialyzers that are to be reused.     

Prevalence of nontuberculous mycobacteria in water supplies of hemodialysis centers.

Infection of hemodialysis patients with nontuberculous mycobacteria (NTM) has been associated with water used in reprocessing hemodialyzers. This study was conducted to determine the prevalence of NTM and other bacteria in water samples collected over a 13-week period from 115 randomly selected dialysis centers in the United States. Total viable counts were determined by membrane filter assays; increased recovery of NTM was obtained by dosing a portion of each water sample with 1% formaldehyde (HCHO) before filtering. NTM were widely distributed and occurred with a high frequency in water supplies in dialysis centers. NTM were detected in water from 95 centers (83%), and 50% of all samples examined contained NTM. The results of this study support recommendations to use 4% HCHO or a chemical germicidal equivalent for disinfecting dialyzers that are to be reused.     

Changes in survival among elderly patients initiating dialysis from 1990 to 1999

Background

Over the past decade, there has been a steep rise in the number of people with complex medical problems who require dialysis. We sought to determine the life expectancy of elderly patients after starting dialysis and to identify changes in survival rates over time.

Methods

All patients aged 65 years or older who began dialysis in Canada between 1990 and 1999 were identified from the Canadian Organ Replacement Register. We used Cox proportional hazards models to examine the effect that the period during which dialysis was initiated (era 1, 1990–1994; era 2, 1995–1999) had on patient survival, after adjusting for diabetes, sex and comorbidity. Patients were followed from initiation of dialysis until death, transplantation, loss to follow-up or study end (Dec. 31, 2004).

Results

A total of 14 512 patients aged 65 years or older started dialysis between 1990 and 1999. The proportion of these patients who were 75 years or older at the start of dialysis increased from 32.7% in era 1 (1990–1994) to 40.0% in era 2 (1995–1999). Despite increased comorbidity over the 2 study periods, the unadjusted 1-, 3- and 5-year survival rates among patients aged 65–74 years at dialysis initiation rose from 74.4%, 44.9% and 25.8% in era 1 to 78.1%, 51.5% and 33.5% in era 2. The respective survival rates among those aged 75 or more at dialysis initiation increased from 67.2%, 32.3% and 14.2% in era 1 to 69.0%, 36.7% and 20.3% in era 2. This survival advantage persisted after adjustment for diabetes, sex and comorbidity in both age groups (65–74 years: hazard ratio [HR] 0.76, 95% confidence interval [CI] 0.72–0.81; 75 years or more: HR 0.86, 95% CI 0.80–0.92).

Interpretation

Survival after dialysis initiation among elderly patients has improved from 1990 to 1999, despite an increasing burden of comorbidity. Physicians may find these data useful when discussing prognosis with elderly patients who are initiating dialysis.Within general medical and subspecialty areas, chronic kidney disease is increasingly recognized as an important comorbid condition that is often associated with prolonged hospital stays and increased morbidity and mortality.^1–3 As a result, internists and other specialists are more likely than before to be involved with the care of patients for whom dialysis needs to be started because of end-stage kidney disease. The majority of patients starting dialysis are 65 years or older at the time of their first treatment, and many are over 75 years.⁴ Given the heightened awareness of chronic kidney disease, its high prevalence, the association with multiple comorbidity, and the impact of dialysis on survival and quality of life, we sought to calculate the mean life expectancy of elderly patients who began dialysis at either 65–74 years of age or at 75 years or more, and to identify whether there was any change in survival probability, or in the effect of comorbidity characteristics, on dialysis over the past decade.     

Cryptococcosis in HIV-negative Patients with Renal Dialysis: A Retrospective Analysis of Pooled Cases

Cryptococcosis is a lethal fungal infection mainly caused by Cryptococcus neoformans/C. gattii species. Currently, our understanding of cryptococcosis episodes in HIV-negative patients during renal dialysis remains scarce and fragmented. Here, we performed an analysis of pooled cases to systemically summarize the epidemiology and clinical characteristics of cryptococcosis among HIV-negative patients with renal dialysis. Using pooled data from our hospital and studies identified in four medical databases, 18 cases were identified and analyzed. The median duration time of renal dialysis for peritoneal renal dialysis and hemodialysis cases was 8 months and 36 months, respectively. Several non-neoformans/gattii species were identified among the renal dialysis recipients with cryptococcosis, particularly Cryptococcus laurentii and Cryptococcus albidus, which share similar clinical manifestations as those caused by C. neoformans and C. gattii. Our analyses suggest that physicians should consider the possibility of the occurrence of cryptococcosis among renal dialysis recipients even when cryptococcal antigen test result is negative. The timely removal of the catheter is crucial for peritoneal dialysis patients with cryptococcosis. In addition, there is a need for optimized antifungal treatment strategy in renal dialysis recipients with cryptococcal infections.     

Antibodies to Dopamine: Radioimmunological Study of Specificity in Relation to Immunocytochemistry

Abstract: Two classes of anti-3,4-dihydroxyphenylethylamine (dopamine) antibodies were raised in rabbits using dopamine conjugated to albumin either via formaldehyde or via glutaraldehyde. Each was usable for immunohistochemical detection of dopamine neurons provided that the tissue was fixed by the homologous cross-linking agent. However, anti-dopamine-glutaraldehyde antibodies turned out to be of more general use because of the better fixative properties of glutaraldehyde which fixed dopamine in rat and in teleost, whereas formaldehyde only worked in lower vertebrates (such as goldfish) and not in rat brain. The specificity of antidopamine-glutaraldehyde antibodies was firmly established by competition experiments in equilibrium dialysis, using an immunoreactive tritiated derivative synthesized by coupling dopamine to N -α-acetyl-L-lysine N -methylamide via glutaraldehyde. Specificity studies in vitro and immunohistological results demonstrating the specific staining of dopaminergic neurons were found to correlate well.     

Comparative analysis of antibody responses to SARS-CoV-2 in various populations

This paper aimed to analyze antibody responses to SARS-CoV-2 in various populations. Two hundred and six COVID-19 patients, 46 convalescent patients, and 270 healthy population were enrolled. Antibodies against nucleocapsid protein (N) and spike protein''s receptor-binding domain (RBD), and neutralizing antibody were detected. The results demonstrated both anti-N and anti-RBD antibodies could be detected in about 80% of COVID-19 patients and 90% of convalescent patients, while no antibodies could be detected in some convalescents and patients even after 14 days post-onset of symptoms. The level of anti-RBD antibody strongly correlated with the neutralizing activity of sera from these two cohorts. The titer of neutralizing antibody was lower in convalescents than that in active COVID-19 patients. In addition, the titer of neutralizing antibody was less than 1:80 in none of the severe COVID-19 patients, 18.8% in non-severe COVID-19 patients, and 32.6% in convalescents. The study suggests that the level of anti-RBD antibody is closely related to neutralization activity in COVID-19 patients and convalescents. Some SARS-CoV-2-infected cases trigger a weak antiviral immune response, and the level of neutralizing antibody may have a faster decay rate.     

Detection of non-pylori Helicobacter species in "Helicobacter heilmannii"-infected humans

BACKGROUND: A small proportion of patients suffering from chronic active gastritis are diagnosed with gastric Helicobacter species other than Helicobacter pylori. Circumstantial evidence has suggested that these bacteria, also referred to as "Helicobacter heilmannii"-like organisms (HHLO), may be transmitted through animals. The isolation of a Helicobacter bizzozeronii strain from a human patient confirmed this hypothesis. It was the aim of the present study to assess the presence of animal Helicobacter species and H. pylori in humans infected with HHLO, as diagnosed by histology. METHODS: Paraffin-embedded gastric biopsy specimens of 108 HHLO-infected patients (42 women and 66 men) from three clinical centers were screened for the presence of animal gastric Helicobacter species by polymerase chain reaction (PCR), using assays targeting the 16S rDNA region of the three known canine and feline helicobacters (H. bizzozeronii, H. salomonis and H. felis), "Candidatus H. suis", and "Candidatus H. bovis". In addition, the presence of H. pylori was evaluated by multiplex PCR analysis. RESULTS: In 63.4% of the stomachs (64/101) classification of the Helicobacter infection into the above mentioned groups was achieved. Non-pylori Helicobacter species commonly colonizing the stomachs of cats and dogs were found in 48.5% (49/101) of the patients. Fourteen (13.9%) samples tested positive for "Candidatus H. suis", and "Candidatus H. bovis" was demonstrated in 1 (0.9%) patient. The presence of H. pylori was established in 13 patients (12.9%). Eleven stomachs (10.9%) were infected with at least two different Helicobacter species. CONCLUSIONS: This study identifies animal Helicobacter species in the stomach of a large series of HHLO-infected patients, which may have clinical implications in a subset of patients with gastric disease.     

Use of APACHE II classification to evaluate outcome of patients receiving hemodialysis in an intensive care unit.

We retrospectively reviewed the medical records of all patients who were admitted to the medical and surgical intensive care units of a university center (N = 100) and its affiliated veterans'' hospital (N = 46) between 1982 and 1986 to receive dialysis. The APACHE II severity-of-disease classification was used to identify the cases in which the prognosis was so poor that no long-term benefit would accrue from hemodialysis treatment. A "risk of death" was calculated for each patient. At a risk of death of 70% or greater, the system correctly predicted the demise of patients with 100% specificity regardless of what interventions were carried out. Sensitivity and predicted negative value were low in all cases, however, indicating a poor predictability of those who will survive. Withholding the average of 6 dialysis treatments that this group of patients received would probably have reduced patient suffering during a lingering terminal illness and led to a savings of about $4,500 per patient.     

Social Welfare Centers Protect Outpatients with Mood Disorders from Risk of Hospital Admission

Background

South Korea faces difficulties in the management of mental disorders, and those difficulties are expected to gradually worsen. Therefore, we analyzed the relationship between social welfare centers and hospital admission after outpatient treatment for mood disorders.

Methods

We used data from the National Health Insurance Service National Sample Cohort 2002–2013, which included all medical claims filed for the 50,160 patients who were newly diagnosed with a mood disorder among the 1,025,340 individuals in a nationally representative sample. We performed a logistic regression analysis using generalized estimating equation (GEE) models to examine the relationship between social welfare centers and hospital admission after outpatient treatment for mood disorders (ICD-10: F3).

Results

There was a 3.9% admission rate among a total of 99,533 person-years. Outpatients who lived in regions with more social welfare centers were less likely to be admitted to a hospital (per increase of five social welfare centers per 100,000 people; OR: 0.958; 95% CI: 0.919–0.999). Social welfare centers had an especially strong protective effect on patients with relatively mild mood disorders and those who were vulnerable to medical expenditures.

Conclusions

Considering the protective role of social welfare centers in managing patients with mood disorders, health-policy makers need to consider strategies for activating mental healthcare.     

Antibody responses to SARS-CoV-2 in patients with COVID-19

This paper aimed to analyze antibody responses to SARS-CoV-2 in various populations. Two hundred and six COVID-19 patients, 46 convalescent patients, and 270 healthy population were enrolled. Antibodies against nucleocapsid protein (N) and spike protein's receptor-binding domain (RBD), and neutralizing antibody were detected. The results demonstrated both anti-N and anti-RBD antibodies could be detected in about 80% of COVID-19 patients and 90% of convalescent patients, while no antibodies could be detected in some convalescents and patients even after 14 days post-onset of symptoms. The level of anti-RBD antibody strongly correlated with the neutralizing activity of sera from these two cohorts. The titer of neutralizing antibody was lower in convalescents than that in active COVID-19 patients. In addition, the titer of neutralizing antibody was less than 1:80 in none of the severe COVID-19 patients, 18.8% in non-severe COVID-19 patients, and 32.6% in convalescents. The study suggests that the level of anti-RBD antibody is closely related to neutralization activity in COVID-19 patients and convalescents. Some SARS-CoV-2-infected cases trigger a weak antiviral immune response, and the level of neutralizing antibody may have a faster decay rate.     

Anti N1 Cross-Protecting Antibodies Against H5N1 Detected in H1N1 Infected People

The A(H5N1) influenza virus pandemic may be the result of avian H5N1 adapting to humans, leading to massive human to human transmission in a context of a lack of pre-existing immunity. As A(H1N1) and A(H5N1) share the same neuraminidase subtype, anti-N1 antibodies subsequent to H1N1 infections or vaccinations may confer some protection against A(H5N1). We analysed, by microneutralization assay, the A/Vietnam/1194/04 (H5N1) anti-N1 cross-protection acquired either during A/NewCaledonia/20/99 (H1N1) infection or vaccination. In cases with documented H1N1 infection, H5N1 cross-protection could be observed only in patients born between 1930 and 1950. No such protection was detected in the sera of vaccinated individuals.     

Rabies virus antinucleoprotein antibody protects against rabies virus challenge in vivo and inhibits rabies virus replication in vitro.

We previously reported that A/WySnJ mice vaccinated via a tail scratch with a recombinant raccoon poxvirus (RCN) expressing the rabies virus internal structural nucleoprotein (N) (RCN-N) were protected against a street rabies virus (D. L. Lodmell, J. W. Sumner, J.J. Esposito, W.J. Bellini, and L. C. Ewalt, J. Virol. 65:3400-3405, 1991). To improve our understanding of the mechanism(s) of this protection, we investigated whether sera of A/WySnJ mice that had been vaccinated with RCN-N but not challenged with street rabies virus had anti-rabies virus activity. In vivo studies illustrated that mice inoculated in the footpad with preincubated mixtures of anti-N sera and virus were protected. In addition, anti-N sera inoculated into the site of virus challenge protected mice. The antiviral activity of anti-N sera was also demonstrated in vitro. Infectious virus was not detected in cultures 24 h following infection with virus that had been preincubated with anti-N sera. At later time points, infectious virus was detected, but inhibition of viral production was consistently > or = 99% compared with control cultures. The protective and antiviral inhibitory activity of the anti-N sera was identified as anti-N antibody by several methods. First, absorption of anti-N sera with goat anti-mouse immunoglobulin serum, but not normal goat serum, removed the activity. Second, radioimmuno-precipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of sucrose density gradient-fractionated anti-N sera showed that antiviral activity was present only in the fraction containing anti-N antibody. Finally, absorption of anti-N sera with insect cells infected with a baculovirus expressing the N protein removed the protective activity. These data indicate that anti-N antibody is a component of the resistance to rabies virus infections.     

Patient load and medical staffing in adult dialysis units in the United Kingdom.

A survey of medical staffing in 50 adult dialysis units in the United Kingdom in 1986 showed a wide range of patient to staff ratios or staffing score ratios. The total patient load (patients receiving haemodialysis in hospital and at home and those receiving continuous ambulatory peritoneal dialysis) varied from 12 to 270 per unit. Patients receiving acute haemodialysis or who had received a transplant were not included. The unit staffing score, on a weighted scale based on experience, varied from 6.0 to 40.5. Previous surveys have all been regionally or nationally based so criteria for assessing the adequacy of staffing in single units do not exist. This survey attempts to provide a guideline by describing the range of medical staffing compared with patient load in single dialysis units. No unit considered itself to be overstaffed, and several considered themselves to be greatly understaffed. Individual dialysis units should plead their own case in the light of their own circumstances and up to date information provided in nationwide staffing surveys such as this one.     

Autotrophic synthesis of activated acetic acid from two CO2 in Methanobacterium thermoautotrophicum

In a previous study with Methanobacterium thermoautotrophicum evidence was presented that methanogenesis and autotrophic synthesis of activated acetic acid from CO₂ are linked processes. In this study one-carbon metabolism was investigated with growing cultures and in vitro.Serine was shown to be converted into glycine and activated formaldehyde, but only traces of label from [¹⁴C-3] of serine appeared in biosynthetic one-carbon positions. This seeming discrepancy could be explained if the same activated formaldehyde is an intermediate in biosynthesis and in methanogenesis from CO₂. This hypothesis was supported by demonstrating that [¹⁴C-3] of serine and [¹⁴C] formaldehyde were rapidly converted into methane, but a small portion of the label was also specifically incorporated into the methyl group of acetate. Methane and acetate synthesis in vitro were similarly stimulated by various compounds. These experiments indicate that the methyl of acetate and methane share common one-carbon precursor(s), i.e. methylene tetrahydromethanopterin, which can also be formed enzymatically from C-3 of serine or chemically from formaldehyde.Propyl iodide 20–40 M) and methyl iodide (1–3 M) completely inhibited growth in the dark. This effect was abolished by light. Methane formation was hardly affected. When ¹⁴CH₃I was applied at an only slightly inhibitory concentration, ¹⁴C was incorporated into the methyl of acetate. In vitro, similar effects on [¹⁴C] acetate formation from ¹⁴CO₂ or from [¹⁴C-3] of serine were observed, except that methyl iodide did not inhibit, but even stimulated acetate synthesis. These experiments indicate that a corrinoid is involved in acetate synthesis and probably not in methanogenesis from CO₂; the metal is light-reversibly alkylated and functions in methyl transfer to the acetate methyl.     

Antigenic cross-reactivity between outer membrane proteins of Neisseria meningitidis and commensal Neisseria species

Two mouse sera against outer membrane proteins from a pathogenic Neisseria meningitidis strain and a commensal N. lactamica strain and two human sera from patients recovering from meningococcal meningitis were used to identify antigens common to pathogenic and commensal Neisseria species. Two major antigens of 55 kDa and 32 kDa, present in all N. meningitidis and N. lactamica strains tested, were demonstrable with all the sera used; the 55-kDa protein was iron-regulated. Demonstration of other common antigens was dependent on the serum used: a 65-kDa antigen was visualised with the human and the mouse anti-N. lactamica sera; a 37-kDa antigen identified as the meningococcal ferric binding protein (FbpA) was only detected with the mouse sera, and two antigens of 83 kDa and 15 kDa were only shown with the mouse anti-N. meningitidis serum. The results demonstrate the existence of several outer membrane antigens common to N. lactamica and N. meningitidis strains, in agreement with the hypothesis that natural immunity against meningitis is partially acquired through colonisation by commensal species, and open new perspectives for the design of vaccine formulations and the development of strategies for vaccination against meningitis.     

Predictors and prevalence of latent tuberculosis infection in patients receiving long-term hemodialysis and peritoneal dialysis

Background

Tuberculosis is a common infectious disease in long-term dialysis patients. The prevalence of latent tuberculosis infection (LTBI) in this population is unclear, particularly in those receiving peritoneal dialysis (PD). This study investigated the prevalence of LTBI in patients receiving either hemodialysis (HD) or PD to determine predictors of LTBI and indeterminate results of interferon-gamma release assay.

Methods

Patients receiving long-term (≥3 months) HD or PD from March 2011 to February 2012 in two medical centers were prospectively enrolled. QuantiFERON-Gold in tube (QFT) test was used to determine the status of LTBI after excluding active tuberculosis. The LTBI prevalence was determined in patients receiving different dialysis modes to obtain predictors of LTBI and QFT-indeterminate results.

Results

Of 427 patients enrolled (124 PD and 303 HD), 91 (21.3%) were QFT-positive, 316 (74.0%) QFT-negative, and 20 (4.7%) QFT-indeterminate. The prevalence of LTBI was similar in the PD and HD groups. Independent predictors of LTBI were old age (OR: 1.034 [1.013–1.056] per year increment), TB history (OR: 6.467 [1.985–21.066]), and current smoker (OR: 2.675 [1.061–6.747]). Factors associated with indeterminate QFT results were HD (OR: 10.535 [1.336–83.093]), dialysis duration (OR: 1.113 [1.015–1.221] per year increment), anemia (OR: 8.760 [1.014–75.651]), and serum albumin level (OR: 0.244 [0.086–0.693] per 1 g/dL increment).

Conclusion

More than one-fifth of dialysis patients have LTBI. The LTBI prevalence is similar in PD and HD patients but is higher in the elderly, current smokers, and those with prior TB history. Such patients require closer follow-up. Repeated or alternative test may be required for malnutrition patients who received long length of HD.