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Biotin interference can cause false-negative specific IgE results in patients with anaphylaxis

2022; Elsevier BV; Volume: 10; Issue: 9 Linguagem: Inglês

10.1016/j.jaip.2022.05.021

2213-2201

Nils Scheib, Daniel Bauersachs, Dimitrii Pogorelov, Charlotte Mara Heinrich, Feng He, Carsten Bindslev‐Jensen, Chrysanthi Skevaki, Markus Ollert,

Myasthenia Gravis and Thymoma

Clinical ImplicationsHigh-dose supplemental biotin can ablate allergen-specific IgE detection in sera from patients with a history of allergy or anaphylaxis on the one-step IMMULITE-2000 auto-analyzer. Thus, clinicians relying on this immunoassay should inquire about biotin intake with patients during the visit.Biotin is essential for human metabolism. Normal plasma biotin concentrations range from 0.1 to 0.8 ng/mL in adults consuming the recommended daily dietary dose of 30 μg.1Livaniou E. Evangelatos G.P. Ithakissios D.S. Yatzidis H. Koutsicos D.C. Serum biotin levels in patients undergoing chronic hemodialysis.Nephron. 1987; 46: 331-332Crossref PubMed Scopus (19) Google Scholar The regular use of biotin-rich supplements has substantially increased among the general US adult population over the years, reaching a prevalence of 2.8% in 2016.2Li D. Rooney M.R. Burmeister L.A. Basta N.E. Lutsey P.L. Trends in daily use of biotin supplements among US adults, 1999-2016.JAMA. 2020; 324: 605-607Crossref PubMed Scopus (9) Google Scholar In outpatients, an even higher prevalence was noted (7.7%), whereas the same study revealed that 7.4% of patients in emergency departments presented with elevated plasma biotin levels above 10 ng/mL.3Katzman B.M. Lueke A.J. Donato L.J. Jaffe A.S. Baumann N.A. Prevalence of biotin supplement usage in outpatients and plasma biotin concentrations in patients presenting to the emergency department.Clin Biochem. 2018; 60: 11-16Crossref PubMed Scopus (45) Google Scholar Particularly in patients with progressive multiple sclerosis, high oral doses of biotin (100-300 mg/d) are used as adjunct treatment.4Espiritu A.I. Remalante-Rayco P.P.M. High-dose biotin for multiple sclerosis: a systematic review and meta-analyses of randomized controlled trials.Mult Scler Relat Disord. 2021; 55103159Abstract Full Text Full Text PDF PubMed Scopus (2) Google Scholar Both over-the-counter and medically justified intake of biotin bear a considerable risk for interference in routine medical laboratory tests employing a biotin-streptavidin reaction. This can cause serious medical consequences.5Li D. Ferguson A. Cervinski M.A. Lynch K.L. Kyle P.B. AACC Guidance Document on Biotin Interference in Laboratory Tests.J Appl Lab Med. 2020; 5: 575-587Crossref PubMed Scopus (20) Google Scholar Biotin-based immunoassays are also used to detect allergen-specific IgE (sIgE) in allergy diagnosis. As previously issued in an urgent field safety notice (IMC18-02.A.OUS, Siemens Healthcare Diagnostics, Tarrytown, NY) and in the subsequently updated product information, a biotin concentration exceeding 5 ng/mL in the patient samples can cause falsely depressed sIgE results on the IMMULITE platform (Siemens).5Li D. Ferguson A. Cervinski M.A. Lynch K.L. Kyle P.B. AACC Guidance Document on Biotin Interference in Laboratory Tests.J Appl Lab Med. 2020; 5: 575-587Crossref PubMed Scopus (20) Google Scholar Because the potential impact of biotin interference for allergy diagnosis has yet not been investigated with clinical samples, we sought to determine the interference bias of relevant biotin concentrations in the sera of patients with sensitization to inhalant allergens or with a history of anaphylaxis in commonly used sIgE immunoassays.Oral doses of 20 mg biotin daily lead to a peak plasma concentration of 184 ng/mL (range, 80-355 ng/mL) in healthy adults.6Grimsey P. Frey N. Bendig G. Zitzler J. Lorenz O. Kasapic D. et al.Population pharmacokinetics of exogenous biotin and the relationship between biotin serum levels and in vitro immunoassay interference.Int J Pharmacokinet. 2017; 2: 247-256Crossref Google Scholar However, with 300 mg/d, which is used by physicians for multiple sclerosis, peak plasma concentrations of 824 ± 303 ng/mL were measured.7Peyro Saint Paul L. Debruyne D. Bernard D. Mock D.M. Defer G.L. Pharmacokinetics and pharmacodynamics of MD1003 (high-dose biotin) in the treatment of progressive multiple sclerosis.Expert Opin Drug Metab Toxicol. 2016; 12: 327-344Crossref PubMed Scopus (68) Google Scholar Therefore, we tested the potential interference by spiking sera with concentrations observed after higher-dose intake of biotin as a food supplement or for medical reasons (300-1,200 ng/mL).8Scheib N. Bauersachs D. Pogorelov D. Heinrich C.M. Hefeng F.Q. Bindslev-Jensen C. et al.Supplementary Information for the paper: Biotin interference can cause false-negative specific IgE results in patients with anaphylaxis.BioStudies. 1989; https://www.ebi.ac.uk/biostudies/studies/S-BSST827Google Scholar We first measured sIgE levels in sera of 14 patients sensitized to inhalation allergens (see Table E1 in this article's Online Repository at www.jaci-inpractice.org). As controls without interference, serum from the same patient received diluent only. Patients were stratified according to lower (n = 5), intermediate (n = 4), or higher (n = 5) sIgE levels for each allergen. We compared two biotin-streptavidin–based diagnostic platforms (3gAllergy IMMULITE-2000 and NOVEOS [HYCOR Biomedical, Garden Grove, CA], using a one- and two-step protocol, respectively) with ImmunoCAP (Thermo Fisher Scientific, Phadia AB, Uppsala, Sweden) that lacks a biotin-streptavidin step. In the NOVEOS and ImmunoCAP assays, no biotin interference of sIgE readouts was observed, regardless of patients' sIgE levels (Figure 1A, B). However, adding biotin resulted in a strong reduction in sIgE values using IMMULITE-2000 (mean ± SD: 92% ± 6.1%) (Figure 1, C). Biotin at 300 ng/mL was sufficient to cause a major reduction in sIgE signals (Figure 1, C), rendering all results of low sIgE samples false-negative at the 0.35-kU/L threshold (Figure 1, D). When the lower threshold of 0.1 kU/L was applied, at least three of five samples turned out to be negative (Figure 1, D). In patients with intermediate sIgE levels, half of the samples became negative at 300 and 600 ng/mL biotin at the 0.35-kU/L cutoff, whereas all samples were affected at 1,200 ng/mL biotin. At the threshold of 0.1 kU/L, only one sample was false-negative (Figure 1, E). Sera with higher sIgE levels were affected by biotin through a lowered sIgE result, but not with regard to a positive or negative test result (Figure 1, F). Biotin interference was independent of sIgE allergen specificity (see Figure E1 in this article's Online Repository at www.jaci-inpractice.org).We then investigated biotin interference on the two sIgE assays involving biotin-streptavidin reactions in a cohort of patients with a history of anaphylaxis (n = 18), in which the accuracy of laboratory diagnosis is crucial because erroneous results may cause fatality. We included six patients each with anaphylaxis to either cashew or peanut ingestion, all confirmed by positive oral food challenge tests, and six patients with anaphylaxis after a yellow jacket sting, for whom venom immunotherapy was prescribed. Consistent with inhalant allergens (Figure 1), adding biotin to sera of anaphylactic patients revealed a strong biotin interference with the sIgE readouts in IMMULITE-2000 (mean reduction, 86% and 92% for 184 ng/mL6 and 500 ng/mL7 biotin, respectively) (Figure 2, A). Strikingly, at the 0.35-kU/L threshold, five of six patients with tested cashew anaphylaxis showed false-negative results at both doses of biotin (Figure 2, B). We obtained false-negative results in three and four of six samples of yellow jacket sting anaphylaxis with the addition of 184 and 500 ng/mL biotin, respectively (Figure 2, C). Biotin at 184 ng/mL caused false-negative results in half of the peanut-anaphylactic patients, whereas a higher dose enhanced the false-negative number to five (Figure 2, D). To determine whether biotin interference depended on the sIgE detection threshold, we calculated the cumulative percentages of false negatives for varying sIgE cutoffs at a biotin concentration of 184 ng/mL for IMMULITE-2000 (bar diagrams in Figure 2, B- D). The results showed that lowering the sIgE threshold to 0.1 kU/L reduced but did not eliminate the potential biotin bias, especially in cashew- and yellow jacket–allergic patients. In an integrated analysis of all 18 anaphylactic patient samples, we observed significant interference of both biotin concentrations on sIgE values (Figure 2, E) (P = 8.8 × 10-17 and 2 × 10-16 for 184 and 500 ng/mL biotin, respectively, employing the t test using Satterthwaite's method, lmer from R). In the NOVEOS assay, the tested biotin concentrations had no effect on the 18 anaphylactic patients (Figure 2, A and F-H).Figure 2Biotin interference in specific IgE (sIgE) immunoassays testing sera of anaphylactic patients. (A) Percentage change of sIgE on IMMULITE-2000 and NOVEOS. (B-H) Green digits represent the number of false-negative sIgE values. (B-D) Cumulative distribution percentages for varying sIgE cutoff values measured by IMMULITE-2000 within each indicated allergen group. Diagnostic threshold, 0.35 kU/L. P was determined by a linear mixed model (∗∗∗P ≤ .001, lmer from R).View Large Image Figure ViewerDownload Hi-res image Download (PPT)We demonstrated in the sera of two cohorts of allergic patients that an excess of biotin can lead to false-negative sIgE results in the one-step biotin-streptavidin–based IMMULITE-2000 assay. To avoid a potential negative impact on patients, laboratories using IMMULITE and connected physicians need to be aware of the details of medication or the dietary history related to biotin intake before sIgE testing. In this case, discontinuation of biotin for 3 to 4 days is recommended based on its elimination half-life.9Bitsch R. Salz I. Hotzel D. Studies on bioavailability of oral biotin doses for humans.Int J Vitam Nutr Res. 1989; 59: 65-71PubMed Google Scholar If discontinuation is not possible for medical reasons, the a priori informed laboratory has several mitigation strategies to circumvent biotin interference.10Bowen R. Benavides R. Colón-Franco J.M. Katzman B.M. Muthukumar A. Sadrzadeh H. et al.Best practices in mitigating the risk of biotin interference with laboratory testing.Clin Biochem. 2019; 74: 1-11Crossref PubMed Scopus (26) Google Scholar Although our in vitro spiking experiments demonstrated a biotin bias in sIgE testing using clinical samples, future studies should also analyze sera of allergic patients at different intervals after oral administration of biotin supplements. Clinical ImplicationsHigh-dose supplemental biotin can ablate allergen-specific IgE detection in sera from patients with a history of allergy or anaphylaxis on the one-step IMMULITE-2000 auto-analyzer. Thus, clinicians relying on this immunoassay should inquire about biotin intake with patients during the visit. High-dose supplemental biotin can ablate allergen-specific IgE detection in sera from patients with a history of allergy or anaphylaxis on the one-step IMMULITE-2000 auto-analyzer. Thus, clinicians relying on this immunoassay should inquire about biotin intake with patients during the visit. High-dose supplemental biotin can ablate allergen-specific IgE detection in sera from patients with a history of allergy or anaphylaxis on the one-step IMMULITE-2000 auto-analyzer. Thus, clinicians relying on this immunoassay should inquire about biotin intake with patients during the visit. Biotin is essential for human metabolism. Normal plasma biotin concentrations range from 0.1 to 0.8 ng/mL in adults consuming the recommended daily dietary dose of 30 μg.1Livaniou E. Evangelatos G.P. Ithakissios D.S. Yatzidis H. Koutsicos D.C. Serum biotin levels in patients undergoing chronic hemodialysis.Nephron. 1987; 46: 331-332Crossref PubMed Scopus (19) Google Scholar The regular use of biotin-rich supplements has substantially increased among the general US adult population over the years, reaching a prevalence of 2.8% in 2016.2Li D. Rooney M.R. Burmeister L.A. Basta N.E. Lutsey P.L. Trends in daily use of biotin supplements among US adults, 1999-2016.JAMA. 2020; 324: 605-607Crossref PubMed Scopus (9) Google Scholar In outpatients, an even higher prevalence was noted (7.7%), whereas the same study revealed that 7.4% of patients in emergency departments presented with elevated plasma biotin levels above 10 ng/mL.3Katzman B.M. Lueke A.J. Donato L.J. Jaffe A.S. Baumann N.A. Prevalence of biotin supplement usage in outpatients and plasma biotin concentrations in patients presenting to the emergency department.Clin Biochem. 2018; 60: 11-16Crossref PubMed Scopus (45) Google Scholar Particularly in patients with progressive multiple sclerosis, high oral doses of biotin (100-300 mg/d) are used as adjunct treatment.4Espiritu A.I. Remalante-Rayco P.P.M. High-dose biotin for multiple sclerosis: a systematic review and meta-analyses of randomized controlled trials.Mult Scler Relat Disord. 2021; 55103159Abstract Full Text Full Text PDF PubMed Scopus (2) Google Scholar Both over-the-counter and medically justified intake of biotin bear a considerable risk for interference in routine medical laboratory tests employing a biotin-streptavidin reaction. This can cause serious medical consequences.5Li D. Ferguson A. Cervinski M.A. Lynch K.L. Kyle P.B. AACC Guidance Document on Biotin Interference in Laboratory Tests.J Appl Lab Med. 2020; 5: 575-587Crossref PubMed Scopus (20) Google Scholar Biotin-based immunoassays are also used to detect allergen-specific IgE (sIgE) in allergy diagnosis. As previously issued in an urgent field safety notice (IMC18-02.A.OUS, Siemens Healthcare Diagnostics, Tarrytown, NY) and in the subsequently updated product information, a biotin concentration exceeding 5 ng/mL in the patient samples can cause falsely depressed sIgE results on the IMMULITE platform (Siemens).5Li D. Ferguson A. Cervinski M.A. Lynch K.L. Kyle P.B. AACC Guidance Document on Biotin Interference in Laboratory Tests.J Appl Lab Med. 2020; 5: 575-587Crossref PubMed Scopus (20) Google Scholar Because the potential impact of biotin interference for allergy diagnosis has yet not been investigated with clinical samples, we sought to determine the interference bias of relevant biotin concentrations in the sera of patients with sensitization to inhalant allergens or with a history of anaphylaxis in commonly used sIgE immunoassays. Oral doses of 20 mg biotin daily lead to a peak plasma concentration of 184 ng/mL (range, 80-355 ng/mL) in healthy adults.6Grimsey P. Frey N. Bendig G. Zitzler J. Lorenz O. Kasapic D. et al.Population pharmacokinetics of exogenous biotin and the relationship between biotin serum levels and in vitro immunoassay interference.Int J Pharmacokinet. 2017; 2: 247-256Crossref Google Scholar However, with 300 mg/d, which is used by physicians for multiple sclerosis, peak plasma concentrations of 824 ± 303 ng/mL were measured.7Peyro Saint Paul L. Debruyne D. Bernard D. Mock D.M. Defer G.L. Pharmacokinetics and pharmacodynamics of MD1003 (high-dose biotin) in the treatment of progressive multiple sclerosis.Expert Opin Drug Metab Toxicol. 2016; 12: 327-344Crossref PubMed Scopus (68) Google Scholar Therefore, we tested the potential interference by spiking sera with concentrations observed after higher-dose intake of biotin as a food supplement or for medical reasons (300-1,200 ng/mL).8Scheib N. Bauersachs D. Pogorelov D. Heinrich C.M. Hefeng F.Q. Bindslev-Jensen C. et al.Supplementary Information for the paper: Biotin interference can cause false-negative specific IgE results in patients with anaphylaxis.BioStudies. 1989; https://www.ebi.ac.uk/biostudies/studies/S-BSST827Google Scholar We first measured sIgE levels in sera of 14 patients sensitized to inhalation allergens (see Table E1 in this article's Online Repository at www.jaci-inpractice.org). As controls without interference, serum from the same patient received diluent only. Patients were stratified according to lower (n = 5), intermediate (n = 4), or higher (n = 5) sIgE levels for each allergen. We compared two biotin-streptavidin–based diagnostic platforms (3gAllergy IMMULITE-2000 and NOVEOS [HYCOR Biomedical, Garden Grove, CA], using a one- and two-step protocol, respectively) with ImmunoCAP (Thermo Fisher Scientific, Phadia AB, Uppsala, Sweden) that lacks a biotin-streptavidin step. In the NOVEOS and ImmunoCAP assays, no biotin interference of sIgE readouts was observed, regardless of patients' sIgE levels (Figure 1A, B). However, adding biotin resulted in a strong reduction in sIgE values using IMMULITE-2000 (mean ± SD: 92% ± 6.1%) (Figure 1, C). Biotin at 300 ng/mL was sufficient to cause a major reduction in sIgE signals (Figure 1, C), rendering all results of low sIgE samples false-negative at the 0.35-kU/L threshold (Figure 1, D). When the lower threshold of 0.1 kU/L was applied, at least three of five samples turned out to be negative (Figure 1, D). In patients with intermediate sIgE levels, half of the samples became negative at 300 and 600 ng/mL biotin at the 0.35-kU/L cutoff, whereas all samples were affected at 1,200 ng/mL biotin. At the threshold of 0.1 kU/L, only one sample was false-negative (Figure 1, E). Sera with higher sIgE levels were affected by biotin through a lowered sIgE result, but not with regard to a positive or negative test result (Figure 1, F). Biotin interference was independent of sIgE allergen specificity (see Figure E1 in this article's Online Repository at www.jaci-inpractice.org). We then investigated biotin interference on the two sIgE assays involving biotin-streptavidin reactions in a cohort of patients with a history of anaphylaxis (n = 18), in which the accuracy of laboratory diagnosis is crucial because erroneous results may cause fatality. We included six patients each with anaphylaxis to either cashew or peanut ingestion, all confirmed by positive oral food challenge tests, and six patients with anaphylaxis after a yellow jacket sting, for whom venom immunotherapy was prescribed. Consistent with inhalant allergens (Figure 1), adding biotin to sera of anaphylactic patients revealed a strong biotin interference with the sIgE readouts in IMMULITE-2000 (mean reduction, 86% and 92% for 184 ng/mL6 and 500 ng/mL7 biotin, respectively) (Figure 2, A). Strikingly, at the 0.35-kU/L threshold, five of six patients with tested cashew anaphylaxis showed false-negative results at both doses of biotin (Figure 2, B). We obtained false-negative results in three and four of six samples of yellow jacket sting anaphylaxis with the addition of 184 and 500 ng/mL biotin, respectively (Figure 2, C). Biotin at 184 ng/mL caused false-negative results in half of the peanut-anaphylactic patients, whereas a higher dose enhanced the false-negative number to five (Figure 2, D). To determine whether biotin interference depended on the sIgE detection threshold, we calculated the cumulative percentages of false negatives for varying sIgE cutoffs at a biotin concentration of 184 ng/mL for IMMULITE-2000 (bar diagrams in Figure 2, B- D). The results showed that lowering the sIgE threshold to 0.1 kU/L reduced but did not eliminate the potential biotin bias, especially in cashew- and yellow jacket–allergic patients. In an integrated analysis of all 18 anaphylactic patient samples, we observed significant interference of both biotin concentrations on sIgE values (Figure 2, E) (P = 8.8 × 10-17 and 2 × 10-16 for 184 and 500 ng/mL biotin, respectively, employing the t test using Satterthwaite's method, lmer from R). In the NOVEOS assay, the tested biotin concentrations had no effect on the 18 anaphylactic patients (Figure 2, A and F-H). We demonstrated in the sera of two cohorts of allergic patients that an excess of biotin can lead to false-negative sIgE results in the one-step biotin-streptavidin–based IMMULITE-2000 assay. To avoid a potential negative impact on patients, laboratories using IMMULITE and connected physicians need to be aware of the details of medication or the dietary history related to biotin intake before sIgE testing. In this case, discontinuation of biotin for 3 to 4 days is recommended based on its elimination half-life.9Bitsch R. Salz I. Hotzel D. Studies on bioavailability of oral biotin doses for humans.Int J Vitam Nutr Res. 1989; 59: 65-71PubMed Google Scholar If discontinuation is not possible for medical reasons, the a priori informed laboratory has several mitigation strategies to circumvent biotin interference.10Bowen R. Benavides R. Colón-Franco J.M. Katzman B.M. Muthukumar A. Sadrzadeh H. et al.Best practices in mitigating the risk of biotin interference with laboratory testing.Clin Biochem. 2019; 74: 1-11Crossref PubMed Scopus (26) Google Scholar Although our in vitro spiking experiments demonstrated a biotin bias in sIgE testing using clinical samples, future studies should also analyze sera of allergic patients at different intervals after oral administration of biotin supplements. Online RepositoryTable E1Characterization of patients, with relevant clinical serology of 14 patients with diagnostic workup for airway allergic symptoms and 18 with confirmed clinical history of anaphylaxisSample ID∗Serum samples from 14 patients with suspected AA and confirmed mSens to a seasonal or perennial allergen were included in Part 1 (IDs 1-AA to 14-AA) and from 18 patients with a history of AX to foods (cashew or peanut) or yellow jacket (Vespula spp.) stings in Part 2 (IDs 15-AX to 32-AX).AllergenOriginal ImmunoCAP, kUA/LClinical information1-AAD001–house dust mite1.29–low†For each allergen, one sample each with a lower, medium, and higher level of sIgE was selected, except for timothy grass (G6), for which only two samples (low and high) were used (indicated low, intermediate, and high behind the specific IgE value).Dx AA, confirmed mSens2-AAD001–house dust mite4.9 –intermediate†For each allergen, one sample each with a lower, medium, and higher level of sIgE was selected, except for timothy grass (G6), for which only two samples (low and high) were used (indicated low, intermediate, and high behind the specific IgE value).Dx AA, confirmed mSens3-AAD001–house dust mite45.3–high†For each allergen, one sample each with a lower, medium, and higher level of sIgE was selected, except for timothy grass (G6), for which only two samples (low and high) were used (indicated low, intermediate, and high behind the specific IgE value).Dx AA, confirmed mSens4-AAE001–cat dander0.49–lowDx AA, confirmed mSens5-AAE001–cat dander0.74–intermediateDx AA, confirmed mSens6-AAE001–cat dander5.23–highDx AA, confirmed mSens7-AAG006–timothy grass pollen0.64–lowDx AA, confirmed mSens8-AAG006–timothy grass pollen11.9–highDx AA, confirmed mSens9-AAM006–Alternaria alternata3.25–lowDx AA, confirmed mSens10-AAM006–A alternata8.22–intermediateDx AA, confirmed mSens11-AAM006–A alternata10.4–highDx AA, confirmed mSens12-AAT007–white oak pollen0.49–lowDx AA, confirmed mSens13-AAT007–white oak pollen4.23–intermediateDx AA, confirmed mSens14-AAT007–white oak pollen16.7–highDx AA, confirmed mSens15-AXF202–cashew nut1AX, OFC Pos16-AXF202–cashew nut0.8AX, OFC Pos17-AXF202–cashew nut1.3AX, OFC Pos18-AXF202–cashew nut0.5AX, OFC Pos19-AXF202–cashew nut0.8AX, OFC Pos20-AXF202–cashew nut42.4AX, OFC Pos21-AXI003–yellow jacket venom1AX, VIT YJV22-AXI003–yellow jacket venom1.7AX, VIT YJV23-AXI003–yellow jacket venom0.6AX, VIT YJV24-AXI003–yellow jacket venom1.6AX, VIT YJV25-AXI003–yellow jacket venom2.9AX, VIT YJV26-AXI003–yellow jacket venom45.7AX, VIT YJV27-AXF013–peanut1.7AX, OFC Pos28-AXF013–peanut0.6AX, OFC Pos29-AXF013–peanut1.2AX, OFC Pos30-AXF013–peanut0.9AX, OFC Pos31-AXF013–peanut0.9AX, OFC Pos32-AXF013–peanut46.7AX, OFC PosAA, airway allergy; AX, anaphylaxis; Dx, diagnostic workup; mSens, monosensitization; OFC Pos, positive oral food challenge outcome; VIT, venom immunotherapy; YJV, yellow jacket venom.IgE is presented as kilounits of allergen-specific IgE per liter and was detected on ImmunoCAP.∗ Serum samples from 14 patients with suspected AA and confirmed mSens to a seasonal or perennial allergen were included in Part 1 (IDs 1-AA to 14-AA) and from 18 patients with a history of AX to foods (cashew or peanut) or yellow jacket (Vespula spp.) stings in Part 2 (IDs 15-AX to 32-AX).† For each allergen, one sample each with a lower, medium, and higher level of sIgE was selected, except for timothy grass (G6), for which only two samples (low and high) were used (indicated low, intermediate, and high behind the specific IgE value). Open table in a new tab AA, airway allergy; AX, anaphylaxis; Dx, diagnostic workup; mSens, monosensitization; OFC Pos, positive oral food challenge outcome; VIT, venom immunotherapy; YJV, yellow jacket venom. IgE is presented as kilounits of allergen-specific IgE per liter and was detected on ImmunoCAP.