Test for Chronic Granulomatous Disease (CGD)
Previously, the nitroblue tetrazolium (NBT) test was the recognized diagnostic test for CGD. Relying on light microscopy, the NBT test relies on a subjective analysis of phagocyte nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity.1
The dihydrorhodamine (DHR) test is the most common test for identifying CGD
While some physicians still use the NBT test, it has been largely replaced by the flow cytometric DHR test.1
The DHR test has user-friendly steps and provides standardized and quantifiable results alongside enhanced sensitivity.1
The DHR test produces fewer false-negative results than the NBT test and is known for its2,3:
May distinguish between X-linked and autosomal recessive forms of CGD
Ability to evaluate X-linked carriers possibly at risk for infections
High sensitivity that can detect low levels of NADPH activity
Ability to quantitatively assess residual superoxide production
Testing may help identify patients before a serious infection occurs.
See how timely management of CGD can help
The DHR test has largely replaced the NBT test to diagnose CGD.1
If you suspect CGD, get a DHR Collection Kit at no cost to confirm a diagnosis
What to look for when reading DHR histograms: Examples of pre- and post-activation DHR histograms
INDIVIDUAL WITHOUT CGD
The histograms show the difference in neutrophil NADPH oxidase activity in both an unstimulated sample and a sample that has been stimulated with PMA. There is a strong shift on the x-axis after PMA stimulation, indicating normal, robust neutrophil NADPH oxidase activity.
PATIENT WITH X-LINKED CGD
The histogram for the stimulated sample shows almost no shift along the x-axis, indicating an absence of neutrophil oxidative burst due to defective NADPH oxidase function.
X-LINKED FEMALE CGD CARRIER
The stimulated sample shows 2 populations of cells. In one population, there is minimal shift along the x-axis because of the absence of NADPH oxidase activity. The other population does have NADPH oxidase activity, as indicated by the shift along the x-axis to the right. This is a sample only and is not inclusive of the various possible results for X-linked carriers.
PATIENT WITH AUTOSOMAL RECESSIVE CGD
The stimulated sample shows a low degree of neutrophil NADPH oxidase activity, as demonstrated by a shift to the right along the x-axis that is much less dramatic than in histograms of patients with X-linked CGD along the x-axis. Both males and females can present with autosomal recessive CGD.
Early identification of X-linked CGD carriers—often recognized following the diagnosis of an affected relative—is critical to mitigating disease progression and reducing the risk of adverse outcomes.
An X-linked carrier with a DHR level under 20% is at increased risk of infection.6‡
An X-linked carrier with a DHR level under 10% is highly associated with infection.6‡
These values are representations of possible DHR outcomes. Because of heterogeneity in disease severity and genotype, outcomes will vary. Laboratory results typically include percentage (%) of residual oxidative burst values.
See a patient case demonstrating how DHR values may change over time
Review tips for proper use of the DHR Collection Kit
Abbreviations: MFI, mean fluorescence intensity; PMA, phorbol myristate acetate
*PMA is an activator used to stimulate neutrophil NADPH oxidase activity.
†Usually a female with a healthy and a mutated allele for gp91phox.
Adapted from Leiding JW, et al (2013)3 and Jirapongsananuruk O, et al (2003).7
‡Symptomatic autoimmunity does not correlate with DHR levels, but is associated with the carrier state.6
See how to use the DHR
Collection Kit
Discover the importance of testing family
members of CGD patients
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References:
1. Yu JE, Azar AE, Chong HJ, Jongco AM III, Prince BT. Considerations in the diagnosis of chronic granulomatous disease. J Pediatric Infect Dis Soc. 2018;7(suppl 1):S6-S11. 2. Kuhns DB, Alvord WG, Heller T, et al. Residual NADPH oxidase and survival in chronic granulomatous disease. N Engl J Med. 2010;363(27):2600-2610. 3. Leiding JW, Holland SM. Chronic granulomatous disease. In: Pagon RA, Adam MP, Ardinger HH, et al, eds. GeneReviews®. Seattle, WA: University of Washington, Seattle; 1993-2022. 4. Choi J, Kane T, Propst L, Spencer S, Kostialik J, Arjunan A. Not just carriers: experiences of X-linked female heterozygotes. J Assist Reprod Genet. 2021 Oct;38(10):2757-2767. 5. Hauck F, Koletzko S, Walz C, et al. Diagnostic and treatment options for severe IBD in female X-CGD carriers with non-random X-inactivation. J Crohns Colitis 6. Marciano BE, Zerbe CS, Falcone EL, et al. X-linked carriers of chronic granulomatous disease: illness, lyonization, and stability. J Allergy Clin Immunol. 2018 Jan;141(1):365-371. 7. Jirapongsananuruk O, Malech HL, Kuhns DB, et al. Diagnostic paradigm for evaluation of male patients with chronic granulomatous disease, based on the dihydrorhodamine 123 assay. J Allergy Clin Immunol. 2003;111(2):374-379.
