Analytical interference in serum iron determination reveals iron versus gadolinium transmetallation with linear gadolinium-based contrast agents

Effect of Interleukin and Hepcidin in Anemia of Chronic Diseases

Background

Anemia of chronic disease (ACD) also termed as the anemia of inflammation has been found to be associated with inflammations, chronic infections, and cancers, particularly in old age. Recent studies revealed that interleukin-6 (IL-6), a proinflammatory cytokine, and hepcidin, an antimicrobial hepatic peptide, play a key role in ACD pathogenesis. Patients and Methods. The study included 40 subjects with chronic diseases and 40 normal subjects of the same age group. Red cell indices, levels of IL-6 and hepcidin, and iron profile were measured in all participants using Bayer ADVIA 120, VITROS 5600, Integrated System/2008, and ELISA assay, respectively.

Results

The level of hemoglobin was considerably less in patients of chronic diseases referred to as "cases" than the normal subjects or "controls" (8.7 ± 1.5 vs. 13.2 ± 0.9). Red blood corpuscle (RBC) count, hematocrit (HCT) level, serum iron, mean corpuscular hemoglobin concentration (MCHC), and serum total iron-binding capacity (TIBC) were found to be significantly lower in the cases as compared to controls (p < 0.001). Serum IL-6 and hepcidin levels were substantially higher in the cases than in the controls (p < 0.001). Serum IL-6 and hepcidin levels were substantially higher in the cases than in the controls (p < 0.001). Serum IL-6 and hepcidin levels were substantially higher in the cases than in the controls (.

Conclusion

This study detected a significant increase in serum IL-6 and hepcidin levels in patients with ACD than the controls. These findings offer an insight into the role played by both cytokine and peptide in the pathogenesis of ACD and thus provide a rationale for future use of novel drugs inhibiting their effects on iron metabolism.

How Do Contrast Agents Affect Cardiac Markers and Coagulation Tests? Experimental Study

Background:

The discovery that biotin interferes with results of troponin and Nt-proBNP led some commercial firms to update their measurement methods. In particular, the clinical incompatibility of cardiac test results may affect the risk of morbidity and mortality.

Objective:

The aim of this study is to investigate the interference effects of 7 different contrast agents on cardiac markers (Troponin-I, Nt-proBNP, Mass CK-MB, CK, AST, LDH) and in coagulation tests (PT, APTT).

Methods:

Seven different contrast media were added into control materials by using interference protocol. The concentrations of PT, APTT, CK, AST, LDH, Mass CK-MB, Troponin-I, and Nt-proBNP were measured by Sysmex CS-2100, Abbott c16000, Siemens Centaur XP and AFİAS-6 analyzer. The number of deviations from target values was calculated.

Results:

The 7 different contrast media caused negative interference in troponin levels between 57.43% and 62.87%. It was found that different contrast media produced false negativity in the Nt-proBNP test, ranging from 6.11% to 96.01%. Enzymes and coagulation tests were less affected.

Conclusion:

Different contrast media may cause false negatives in cTnI and Nt-proBNP. The contrast medium that causes the least interference should be preferred. The results of samples taken in the first hour after contrast imaging should be interpreted with care.

Dechelation (Transmetalation): Consequences and Safety Concerns With the Linear Gadolinium-Based Contrast Agents, In View of Recent Health Care Rulings by the EMA (Europe), FDA (United States), and PMDA (Japan)

The issue of dechelation (transmetallation) in vivo after administration of the linear gadolinium-based contrast agents, and potential safety concerns, is considered on the basis of an extensive, focused literature review. Early indications of potential problems included the high level of excess ligand used in the formulation of 2 agents (indeed the 2 least stable thermodynamically) and interference with laboratory tests when blood was drawn from patients relatively soon after administration of these same agents. The advent of nephrogenic systemic fibrosis in the late 2000s raised additional major concerns.The correlation in 2014 of dentate nucleus hyperintensity on precontrast T1-weighted scans with multiple prior injections of linear gadolinium chelates, in patients with normal renal function, has driven subsequent research concerning dechelation of these agents in vivo. Unexpectedly high levels of gadolinium in the bone, skin, and liver have been found long term after administration, in animal models and in humans, although the latter data are limited. Bone may serve as a long-term reservoir, with a residual excretion phase for gadolinium after intravenous injection of the linear agents due to a subsequent slow release from bone. Many different patient populations could be vulnerable and potentially later develop clinical symptoms, although at this stage there are only limited data and small retrospective uncontrolled studies. Possible vulnerable populations include children, menopausal women, patients with osteoporosis (who are predisposed to fractures and often slow to heal or heal poorly), those receiving multiple doses, those with proinflammatory conditions, moderate renal dysfunction, or an undefined genetic predisposition. Of particular concern would be nephrogenic systemic fibrosis-like symptoms-including particularly pain and skin/joint symptoms, or disease related to the incorporation of gadolinium in hydroxyapatite in bone, in small subgroups of patients with a not yet defined propensity and/or cofactor. These concerns have led to withdrawal of the linear agents from the largest clinical market, Europe, with the exception of the hepatobiliary agents for delayed liver imaging, an indication that cannot be fulfilled by the current macrocyclic gadolinium chelates (for which these concerns do not apply).

A Review of the Current Evidence on Gadolinium Deposition in the Brain

Over the past 3 years, gadolinium-based contrast agents have been linked to MRI signal changes in the brain, which have been found to be secondary to gadolinium deposition in the brain, particularly in the dentate nuclei and globus pallidus even in patients having an intact blood-brain barrier and a normal renal function. This tends to occur more in linear agents than with macrocyclic agents. Nonetheless, there has been no significant evidence that this has any clinical consequence. We reviewed the current evidence related to this new phenomenon and the precautionary approach taken by regulatory agencies.

Gadolinium-Based Contrast Agent-Related Toxicities

In recent years, gadolinium-based contrast agents have been associated with different types of toxicity. In particular, nephrogenic systemic fibrosis, a progressive sclerotic-myxedematous systemic disease of unknown etiology, is related to gadolinium-based contrast agent administration in patients with kidney dysfunction. More recently, evidence of magnetic resonance signal intensity changes on pre-contrast T1-weighted images after multiple gadolinium-based contrast agent administrations resulted in the hypothesis of gadolinium brain accumulation in patients with normal renal function, subsequently confirmed in pathological samples. However, there is limited current data and further investigations are necessary before drawing definite conclusions on the clinical consequences of gadolinium-based contrast agent accumulation in human tissues and particularly in the brain. Gadolinium-based contrast agent-related toxicity appears connected to molecular stability, which varies together with the pharmacokinetic properties of the compound and depends on the individual characteristics of the subject. During a lifetime, the physiological changes occurring in the human body may influence its interaction with gadolinium-based contrast agents: the integrity and developmental stage of the organs has an effect on the dynamics of gadolinium-based contrast agent distribution and excretion, thus leading to different possible mechanisms of deposition and toxicity. Therefore, the aim of this work is to discuss the pharmacokinetics and pharmacodynamics of gadolinium-based contrast agents, with a special focus on the brain, and to explore potential predominant gadolinium-based contrast agent-related toxicity in two cornerstone periods of the human life cycle: fetal/neonatal and adulthood/aged.

Analytical Interference by Contrast Agents in Biochemical Assays

Objective

To provide a clinically relevant overview of the analytical interference by contrast agents (CA) in laboratory blood test measurements.

Materials and Methods

The effects of five CAs, gadobutrol, gadoterate meglumine, gadoxetate disodium, iodixanol, and iomeprol, were studied on the 29 most frequently performed biochemical assays. One-day-old plasma, serum, and whole blood were spiked with doses of each agent such that the gadolinium agents and the iodine agents reached concentrations of 0.5 mM and 12 mg iodine/mL, respectively. Subsequently, 12 assays were reexamined using 1/2 and 1/4 of these CA concentrations. The results were assessed statistically by a paired Student's t-test.

Results

Iodixanol produced a negative interference on the bicarbonate (p = 0.011), lactate dehydrogenase (p < 0.0001), and zinc (p = 0.0034) assays and a positive interference on the albumin (p = 0.0062), calcium (p < 0.0001), ionized calcium (p = 0.0086), iron (p < 0.0001), and potassium (p = 0.0003) assays. Iomeprol produced a negative interference on the bicarbonate (p = 0.0057) and magnesium (p = 0.0001) assays and a positive interference on the calcium (p < 0.0001) and potassium (p = 0.0012) assays. Gadoxetate disodium produced a negative interference on the iron (p < 0.0001) and zinc (p < 0.0001) assays and a positive interference on the sodium (p = 0.032) assay.

Conclusion

CAs cause analytical interference. Attention should be given to the above-mentioned analyte-CA combinations when assessing laboratory blood test results obtained after CA administration.