Does erythrocyte sedimentation rate (ESR) have diagnostic utility in my patient with chronic renal failure?

Short answer: No! This is because most studies have shown frequently high ESR’s in stable “uninflamed” patients with chronic renal failure (CRF) (including those on dialysis) at levels often associated with infection, connective tissue disease, or malignancy in normal renal function. 1-4  

In fact, in a study involving patients with CRF, 57% of patients had markedly elevation of ESR (greater than 60 mm/h), with 20% having ESR greater than 100 mm/h; type or duration of dialysis had no significant effect on ESR levels.1 Another study reported a specificity for abnormal ESR of only 35% for commonly considered inflammatory conditions (eg, infections or malignancy) among patients with CRF. 2

But is it the chronic inflammation in diseased kidneys or the uremic environment that elevates ESR? A cool study compared ESR in CRF in patients who had undergone bilateral nephrectomies with those with retained kidneys and found no significant difference in the ESR between the 2 groups. 4  So it looks like it’s the uremic environment, not diseased kidneys themselves that result in elevated ESR in these patients.

The mechanism behind these observations seem to reside entirely within the patients’ plasma, not the erythrocytes. Within the plasma, fibrinogen (not gammaglobulins) seem to be the most likely factor explaining elevated ESR among patients with CRF. 1,2

Bonus pearl:  Did you know that ESR is nearly 100 years old, first described in 1921? 5


  1. Barthon J, Graves J, Jens P, et al. The erythrocyte sedimentation rate in end-stage renal failure. Am J Kidney Dis 1987;10: 34-40.
  2. Shusterman N, Morrison G, Singer I. The erythrocyte sedimentation rate and chronic renal failure. Ann Intern Med 1986;105:801.
  3. Arik N, Bedir A, Gunaydin M, et al. Do erythrocyte sedimentation rate and C-reactive protein levels have diagnostic usefulness in patients with renal failure? Nephron 2000;86:224.
  4. Warner DM, George CRP. Erythrocyte sedimentation rate and related factors in end-stage renal failure. Nephron 1991;57:248.
  5. Fahraeus R. The suspension stability of the blood. Acta Med Scan 1921;55:70-92.


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Does erythrocyte sedimentation rate (ESR) have diagnostic utility in my patient with chronic renal failure?

Why is latent tuberculosis usually treated with one antibiotic while active tuberculosis is treated with 2 or more drugs?

Conventional wisdom has been that in active tuberculosis (TB) patients harbor large numbers of replicating Mycobacterium tuberculosis (Mtb), requiring multiple antibiotics to prevent the emergence of resistant mutants. In contrast, Mtb under latent or “inactive” conditions is presumed to have little capacity for mutation due to reduced bacterial replication, thus generally requiring only one antibiotic for preventive therapy.1

However, the assumption that Mtb has a low capacity for mutation in latent TB due to slow bacterial replication has been challenged in recent years. An experimental study in macaque monkeys with latent Mtb infection using whole genome sequencing demonstrated that despite reduced replication, Mtb acquires a similar number of chromosomal mutations during latency as it does during active infection.1

This finding supports the more current and evolving concept of latent TB which assumes diverse mycobacterial growth states, ranging from complete absence of organisms to actively replicating bacterial populations.2 It also explains why, although effective, isoniazid monotherapy may be a risk factor for the emergence of INH resistance in latent TB. 1,3

 Bonus Pearl: Did you know that INH treatment of latent TB in adults is 60-80% protective when given for 6 months, and 90% protective when given for 9 months? 4


  1. Ford CB, Lin PL, Chase M, et al . Use of whole genome sequencing to estimate the mutation rate of Mycobacterium tuberculosis during latent infection. Nat Genet. 2011;43:482-86.
  2. Gideon HP, Flynn JL. Latent tuberculosis: what the host “sees”? Immunol Res 2011;50:202-12.
  3. Balcells ME, Thomas SL, Faussett PG, et al. Isoniazid preventive therapy and risk for resistant tuberculosis. Emerg Infect Dis 2006;12:744-51.
  4. Piccini P, Chiappini E, Tortoli E, et al. Clinical peculiarities of tuberculosis. BMC Infect Dis 2014; 14 (Suppl 1):S4.


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Why is latent tuberculosis usually treated with one antibiotic while active tuberculosis is treated with 2 or more drugs?

How is prealbumin related to albumin?

Aside from being synthesized in the liver and serving as a transport protein in the blood, prealbumin (PA) doesn’t really have much in common with albumin. More specifically, PA is not derived from albumin and, in fact, the two proteins are structurally distinct from each other!

So where does PA get its name? PA is the original name for transthyretin (TTR), a transport protein that primarily carries thyroxine (T4) and a protein bound to retinol (vitamin A). The name arose because TTR migrated faster than albumin on gel electrophoresis of human serum.1

Because of its much shorter serum half-life compared to that of albumin ( ~2 days vs ~20 days),2 PA is more sensitive to recent changes in protein synthesis and more accurately reflects recent dietary intake (not necessarily overall nutritional status) than albumin. 3

But, just like albumin, PA may represent a negative acute phase reactant, as its synthesis drops during inflammatory states in favor of acute phase reactants such as C-reactive protein. 4 So be cautious about interpreting low PA levels in patients with active infection, inflammation or trauma.



  1. Socolow EL, Woeber KA, Purdy RH, et al. Preparation of I-131-labeled human serum prealbumin and its metabolism in normal and sick patients. J. Clin Invest 1965; 44: 1600-1609.
  2. Oppenheimer JH, Surks MI, Bernstein G, and Smith JC. Metabolism of Iodine-131-labeled Thyroxine-Binding Prealbumin in Man. Science 1965; 149: 748-750.
  3. Ingenbleek Y, Young VR. Significance of prealbumin in protein metabolism. Clin Chem Lab Med 2002; 40: 1281-1291.
  4. Shenkin A. Serum prealbumin: is it a marker of nutritional status or of risk of malnutrition? Clin Chem 2006;52:2177 – 2179.


Contributed by Colin Fadzen, Medical Student, Harvard Medical School, Boston, MA.


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How is prealbumin related to albumin?

My patient with COPD exacerbation on corticosteroids has an elevated white blood cell and neutrophil count. How can I tell if his elevated neutrophil count is caused by the corticosteroids or an acute infection?

The most helpful lab data favoring corticosteroid-induced granulocytosis (CIG) is the absence of a shift to the left in the peripheral WBC (ie, no more than 6% band forms) and toxic granulation.1 Although the total WBC itself is less helpful, experimental studies have reported a mean maximum neutrophil counts 2.4 times the base line after IV injection of hydrocortisone (200 mg) 2, and a mean increase of 4,000 neutrophils/mm3 after prednisone (20-80 mg). 3

Several possible mechanisms for CIG revolving around altered neutrophil characteristics and dynamics have been proposed4, including

  • Reduced egress from blood into tissues
  • Demargination from vascular endothelial surfaces
  • Delayed apoptosis
  • Enhanced release from the bone marrow.

An experimental animal study reported that only 10% of CIG is related to bone marrow release of neutrophils with the rest related to demargination (61%) and reduced egress from blood or delayed apoptosis (29%).4 This study may explain why high percentage of band forms would not be expected in CIG.


  1. Shoenfeld Y, Gurewich Y, Gallant LA, et al. Prednisone-induced leukocytosis: influence of dosage, method, and duration of administration on the degree of leukocytosis. Am J Med 1981;71:773-78. Link
  2. Bishop CR, Athens JW, Boggs DR, et al. Leukokinetic studies: A non-steady-state kinetic evaluation of the mechanism of cortisone-induced granulocytosis. J Clin Invest 1986;47:249-60.
  3. Dale DC, Fauci AS, Guerry DuPont, et al. Comparison of agents producing a neutrophilic leukocytosis in man. J Clin Invest 1975;56:808-13. PDF
  4. Nakagawa M, Terashma T, D’yachkova YD, et al. Glucocorticoid-induced granulocytosis: Contribution of marrow release and demargination of intravascular granulocytes. Circulation 1998;98:2307-13. PDF

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My patient with COPD exacerbation on corticosteroids has an elevated white blood cell and neutrophil count. How can I tell if his elevated neutrophil count is caused by the corticosteroids or an acute infection?

Can native valve infective endocarditis be associated with hemolytic anemia?

Yes, but it’s rare!  Hemolytic anemia (HA) in the setting of infective endocarditis (IE) has only been described in a few case reports (1-3).  Although diseased valves may cause shearing stress that fragments RBCs, similar to that associated with mechanical heart valves, an autoimmune hemolytic process has also been implicated. 

A 2018 case report describes a patient with hypertrophic obstructive cardiomyopathy (HOCM) with left ventricular outflow tract (LVOT) obstruction who had HA secondary to subacute IE due to Actinomyces israelii (1).   The anemia completely resolved after treating the IE (1). The cause was most likely mechanical shearing (schistocytes or fragmented RBCs present on peripheral smear) by the diseased valves; autoimmune hemolysis was considered unlikely in this case due to consistently negative Coombs tests and failure to respond to corticosteroids (1). 

An autoimmune mechanism was invoked by a 1999 report reviewing 6 cases of HA associated with IE (3).  All patients had fragmented erythrocytes, but several also demonstrated an immune-mediated mechanism for their HA, supported by the presence of spherocytes, splenomegaly, and + Coombs test (2,3).  The production of anti-erythrocyte antibodies, modification of antigenicity of erythrocyte antigens, or unmasking of antigens in IE may play a role (1,3). Additional evidence in support of an immune-mediated mechanism of HA in IE has been provided by an experimental study demonstrating significantly shorter RBC half-life in rabbits with intact spleen compared to that of splenectomized animals (4).



1. Toom S, Xu Y. Hemolytic anemia due to native valve subacute endocarditis with Actinomyces israellii infection. Clin Case Rep 2018;6: 376-79. 

2. Hsu CM, Lee PI, Chen JM, et al. Fatal Fusarium endocarditis complicated by hemolytic anemia and thrombocytopenia in an infant. Pediatr Infect Dis 1994;13:1146-48. 

3. Huang HL, Lin FC, Hung KC, et al. Hemolytic anemia in native valve infective endocarditis. Jpn Circ J 1999;63:400-403. 

4. Joyce RA, Sand MA. Mechanism of anaemia in experimental bacterial endocarditis. Scand J Haematol 1975;15:306-11. 


Contributed by Scott Goodwin, Medical Student, Harvard Medical School, Boston, MA. 


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Can native valve infective endocarditis be associated with hemolytic anemia?

How can I tell if my febrile patient who uses IV drugs had cotton fever?

Although IV drug use (IVDU) is associated with febrile illness of numerous etiologies (eg, soft tissue infections, pneumonia, bacteremia, endocarditis), certain features of a febrile illness may be helpful in considering cotton fever (CF) as the cause.1-3

First, onset of fever—often associated with chills, shortness of breath, nausea, vomiting, headache, abdominal pain and myalgias—in CF is usually manifest within 10-30 minutes of drug injection. Second, infectious disease workup, including blood cultures and chest radiograph, are unrevealing despite clinical signs of systemic inflammatory response syndrome (SIRS), such as leukocytosis, tachypnea and tachycardia. Third, symptoms and clinical signs of inflammation usually resolve or improve within 6-12 h of onset (less commonly up to 24-48 h). Nevertheless, CF remains a diagnosis of exclusion.

As for the cause of CF, the most widely-held theory revolves around the endotoxin of Pentoea agglomerans (formerly Enterobacter agglomerans), a gram-negative rod that colonizes cotton plants. Since cotton is often used as a filter during injection of illicit substances, any endotoxin present in the cotton is also injected resulting in abrupt onset of a febrile illness. Of note, the toxin is water soluble and heating (often part of the preparation of the drug) enhances its toxic effect.3


  1. Zerr AM, Ku K, Kara A. Cotton Fever: a condition self-diagnosed by IV drug users. JABFM 2016;29: 276-279.PDF
  2. Xie Y, Pope BA, Hunter AJ. Cotton fever: does the patient know best? J Gen Intern Med 31:442-4. PDF
  3. Torka P, Gill S. Cotton fever: an evanescent process mimicking sepsis in an intravenous drug abuser. J Emerg Med 2013;44:e385-e387. PDF
How can I tell if my febrile patient who uses IV drugs had cotton fever?

Why has my patient with Clostridium difficile diarrhea developed Klebsiella bacteremia?

Although there are many potential sources for Klebsiella sp. bacteremia, C. difficile infection (CDI) itself may be associated with GI translocation of enteric organisms.

A retrospective study of over 1300 patients found an incidence of 1.8% for CDI-associated bacteremia. E. coli, Klebsiella sp. , or Enterococcus sp. accounted for 72% of cases. History of malignancy, neutropenia (at the time of CDAD), and younger age (mean 59 y) were among the risk factors.1 Another study reported over 20 cases of bacteremia caused by C. difficile plus other bacteria often of enteric origin such the aforementioned organisms, Bacteroides sp, Candida sp, and Enterobacter sp.2

CDI is thought to predispose to bacterial translocation through the GI tract by alteration of mucosal indigenous microflora, overgrowth of certain pathogens, and presence of inflammation in the mucosa.3 Interestingly, C. difficile toxin A or B may play an active role in the bacterial adherence and penetration of the intestinal epithelial barrier.4  

Bonus pearl: Did you know that C. difficile may be found in the normal intestinal flora of 3% of healthy adults, 15-30% of hospitalized patients, and up to 50% of neonates? Why neonates seem immune to CDI is another fascinating story!



  1. Censullo A, Grein J, Madhusudhan M, et al. Bacteremia associated with Clostridium difficile colitis: incidence, risk factors, and outcomes. Open Forum Infectious Diseases, Volume 2, Issue suppl_1, 1 December 2015, 943,
  2. Kazanji N, Gjeorgjievski M, Yadav S, et al. Monomicrobial vs polymicrobial Clostridum difficile bacteremia: A case report and review of the literature. Am J Med 2015;128:e19-e26.
  3. Naaber P, Mikelsaar RH, Salminen S, et al. Bacterial translocation, intestinal microflora and morphological changes of intestinal mucosa in experimental models of Clostridium difficile infection. J Med Microbiol 1998; 47: 591-8. 
  4. Clostridium difficile toxins may augment bacterial penetration of intestinal epithelium. Arch Surg 1999;134: 1235-1242.
Why has my patient with Clostridium difficile diarrhea developed Klebsiella bacteremia?