Neopterin, a pyrazino-pyrimidine compound, is synthesized by monocytes and macrophages in response to interferon-𝛾 (IFN-γ) produced by activated T cells. Both total neopterin and neopterin reflect cellular immune response, because IFN-γ induces a step that precedes formation of 7,8-dihydroneopterin in the neopterin pathway. Increased concentrations are observed in infections by viruses, including human immunodeficiency virus (HIV), infections by intracellular bacteria and parasites, autoimmune diseases, malignant tumour diseases and in allograft rejection episodes. Neopterin in serum/plasma shows a strong, positive relation to total homocysteine and to the kynurenine/tryptophan ratio (KTR) (2).
Since IFN-g induce a step that precedes formation of 7,8-dihydroneopterin in the neopterin pathway, the use of neopterin and total neopterin both reflect inflammation. The use of total neopterin is further supported by its strong correlation with neopterin in urine (3) and plasma, and it has been suggested that neopterin and total neopterin are of equal value for clinical diagnosis (3).
Assessment of cellular immune response.
Matrix: Plasma and serum. Neopterin increases (up to 100%) in samples with hemolysis.
Volume: Minimum volume is 60 µL, but 200 µL is optimal and allows reanalysis.
Preparation: Samples should be put on ice, and protected from exposure to ultraviolet light and sunlight.
Frozen, on dry ice and protected from exposure to ultraviolet light and sunlight. (for general instruction on transportation, click here)
Total neopterin correlates strongly with neopterin in urine and plasma, and with plasma KTR. Neopterin and total neopterin are of equal value for the assessment of immune activation (3).
Reported values: 5-50 nmol/L.
Intraclass correlation coefficient (ICC): 0.60.
1. Midttun, O., Hustad, S., and Ueland, P.M. (2009). Quantitative profiling of biomarkers related to B-vitamin status, tryptophan metabolism and inflammation in human plasma by liquid chromatography/tandem mass spectrometry. Rapid Commun Mass Sp 23, 1371-79.
2. Capuron, L., Geisler, S., Kurz, K., Leblhuber, F., Sperner-Unterweger, B., and Fuchs, D. (2014). Activated immune system and inflammation in healthy ageing: Relevance for tryptophan and neopterin Metabolism. Curr Pharm Des 20, 6048-057.
3. Fuchs, D., Milstien, S., Krämer, A., Reibnegger, G., Werner, E.R., Goedert, J.J., Kaufman, S., and Wachter, H. (1989). Urinary neopterin concentrations vs total neopterins for clinical utility. Clin Chem 35, 2305-07.
Beate
Øivind
Per Magne Ueland has been Professor at the University of Bergen 1987-2018. He is one of the founders of Bevital AS and the scientific advisor in Bevital since 2023. His interests includes biomarkers related to nutrition, inflammation, ageing and life-style related chronic diseases. Per is committed to the development of precise, high-throughput mass spectrometry methods, tailored for metabolic profiling of biobank specimens from large cohorts.
Ove
Ove completed a bachelor’s degree in Biomedical Laboratory Sciences at the Western Norway University of Applied Sciences in Bergen. With extensive experience in method development and expertise in GC-MS/MS, he specializes in optimizing analytical techniques for research-focused studies. At Bevital, Ove is dedicated to advancing laboratory methods and workflows, contributing to innovative research through precise and reliable analytical solutions.
Lene holds a bachelor’s degree in Biomedical Laboratory Science from the Western Norway University of Applied Sciences, where she is also completing her master’s degree in Medical Laboratory Technology. At Bevital, she works with GC-MS/MS analyses, focusing on accurate and reliable testing of biological samples. With her strong laboratory background, Lene is committed to delivering high-quality results that support medical research.
Klaus holds a PhD in physics from the University of Münster in Germany. He has over three decades of experience in Time-of-Flight mass spectrometry. He leverages his extensive expertise to provide customers with cutting-edge MALDI-MS analysis and the newest Olink Proteomics services.
Adrian holds a PhD in diabetes research, along with bachelor’s and master’s degrees in biomedical science and public health, respectively. With over 20 years of experience in laboratory science, he leads high-precision metabolite analyses and method development at Bevital. His expertise centers on quantifying biomarkers, metabolite classes, and metabolic pathways related to nutrition, cardiovascular and neurodegenerative diseases, and cancer. Adrian is committed to advancing research quality and actively collaborates nationally and internationally, leveraging targeted metabolomics to support innovative, multidisciplinary research.
Statistical power is the probability that a statistical test will correctly reject a false null hypothesis (H0) when a specific alternative hypothesis (H1) is true. H0 is the null hypothesis, which states there is no effect or no difference. H1 is the alternative hypothesis, which states there is a real effect or difference. Alpha (α) is the probability of a Type I error (a false positive), which is the risk of incorrectly rejecting the H0 when it is actually true. You set this value before the experiment, commonly at 0.05. Beta (β) is the probability of a Type II error (a false negative), which is the risk of failing to reject the H0 when it is actually false.
Power is calculated as 1−β. Increasing power means you are decreasing the probability of making a Type II error.
Several factors can be adjusted to increase the power of a statistical test:
Effect Size: This is the magnitude of the difference you are trying to detect. A larger effect size is easier to detect, thus increasing power.
Sample Size: The number of observations in a study. A larger sample size provides more information about the population, reducing the margin of error and increasing the power to detect a true effect.
Variation: Refers to the spread or standard deviation of the data within the population. Less variation makes it easier to distinguish a real effect from random noise, thereby increasing power.
Alpha (α): Increasing the alpha level (e.g., from 0.05 to 0.10) also increases power, but at the cost of a higher risk of a Type I error. This trade-off is often undesirable.

Vollset, S E; Nygârd, O; Refsum, H; Ueland, P M
Coffee and homocysteine Miscellaneous
2000, ISSN: 0002-9165.
@misc{pmid10648251,
title = {Coffee and homocysteine},
author = {S E Vollset and O Nygârd and H Refsum and P M Ueland},
doi = {10.1093/ajcn/71.2.403},
issn = {0002-9165},
year = {2000},
date = {2000-02-01},
journal = {Am J Clin Nutr},
volume = {71},
number = {2},
pages = {403--404},
keywords = {},
pubstate = {published},
tppubtype = {misc}
}
Schneede, J; Refsum, H; Ueland, P M
Biological and environmental determinants of plasma homocysteine Journal Article
In: Semin Thromb Hemost, vol. 26, no. 3, pp. 263–279, 2000, ISSN: 0094-6176.
@article{pmid11011844,
title = {Biological and environmental determinants of plasma homocysteine},
author = {J Schneede and H Refsum and P M Ueland},
doi = {10.1055/s-2000-8471},
issn = {0094-6176},
year = {2000},
date = {2000-01-01},
journal = {Semin Thromb Hemost},
volume = {26},
number = {3},
pages = {263--279},
abstract = {This article gives an overview over common physiological, lifestyle, and pathological conditions that may modulate the homocysteine status. The interplay of several environmental factors, including age, gender, nutrition, smoking, and coffee consumption and physical activity with commonly used drugs and prevalent diseases are described. In most cases, an abnormal homocysteine status is not caused by a single factor alone but often is the result of combined effects. We address these frequently found "clusters" of homocysteine-modulating factors. Finally, we give an overview of likely causes of hyperhomocysteinemia found in an authentic material. This material is based on 2462 routine measurements of plasma total homocysteine carried out at the Haukeland University Hospital. The data represent the total number of combined homocysteine and methylmalonic acid determinations, requested by general practitioners in Norway during February 1998.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
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