Optimizing Diagnostic Protocols for Cow's Milk Allergy in Infants With The Food Allergy IgE Panel

Cow dairy allergies are a common and often challenging condition, especially for children and their families. Understanding these allergies isn't just about reading numbers or medical terms—it's about grasping the real-life impact they have. Imagine the constant vigilance required to read every food label, the frustration of avoiding favorite snacks, and the ongoing quest to find safe, nutritious alternatives. 

For many, this is a daily reality that shapes their diets, social interactions, and overall well-being. This article reviews a cohort study on cow dairy allergies, providing a comprehensive look at how we can better identify and manage this common allergy.

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Study Design

The study was designed as a comprehensive observational cohort study. This design was chosen to observe and analyze the diagnostic methods for cow's milk allergy (CMA) in a real-world clinical setting without manipulating any variables. 

The objective of the study was to evaluate the effectiveness of two specific IgE (sIgE) measurement methods—ImmunoCAP and IMMULITE 2000 3gAllergy—in diagnosing cow's milk allergy (CMA) in infants. 

The study aimed to determine if these methods could improve the selection criteria for infants who should undergo the Oral Food Challenge (OFC), which is considered a reliable method for diagnosing food allergies but can be time-consuming and risky. 

Additionally, the study assessed whether detecting low levels of sIgE (down to 0.1 kU/L) could enhance the identification of individuals with allergies.

The study included 60 infants (27 females and 33 males) referred to the Allergy Service at Sant Joan de Déu Hospital in Barcelona, Spain, for suspected CMA. The average age when symptoms started was 3.5 months, and the average age at diagnosis was 9 months.

Diagnostic Approaches Evaluated

To evaluate the presence of cow milk allergy (CMA) in the infants, several diagnostic methods were used:

• Clinical History: Detailed histories were taken to document symptoms and possible allergic reactions.
• Skin Prick Tests (SPT):
  • Performed on the forearms using extracts of total milk, α-lactalbumin, β-lactoglobulin, and casein.
  • A wheal (raised bump) larger than 3 mm was considered a positive result.
• Specific IgE Measurements: Two methods were used to measure specific IgE antibodies in the blood:
  • ImmunoCAP: A result above 0.35 kU/L was considered positive.
  • IMMULITE 2000 3gAllergy: Positive cutoffs were 0.1 kU/L and 0.2 kU/L.
• Oral Food Challenge (OFC):
  • Conducted over three days with gradually increasing doses of milk.
  • Considered positive if any clinical symptoms appeared during the challenge.

Findings of the Study

Oral Food Challenge (OFC) Results

The Oral Food Challenge (OFC) is considered a reliable method for diagnosing cow's milk allergy (CMA). In this study, 39 children underwent the OFC, while 21 were excluded due to a high risk of anaphylaxis, high specific IgE (sIgE) levels, or lack of parental consent. Among those who underwent the OFC:

• Positive Response: 19 children had a positive response, indicating an allergy to cow's milk.
• Negative Response: 20 children had a negative response, indicating no allergy to cow's milk.

Skin Prick Tests (SPT) Results

The SPTs were performed using extracts of total milk, α-lactalbumin, β-lactoglobulin, and casein. The results showed:

• Specificity: Greater than 85% for all allergens tested.
• Sensitivity: Varied from 38% for casein to 53% for α-lactalbumin. When results for all milk allergen components were combined, the sensitivity was 63%, and specificity was 85%.

Specific IgE Measurements

Two methods for measuring sIgE were evaluated: ImmunoCAP and IMMULITE 2000 3gAllergy. The findings included:

• Agreement with OFC: The agreement between OFC results and the two in vitro methods at their respective positive cutoffs was 80% for 3gAllergy and 72% for ImmunoCAP.
• Sensitivity and Specificity: The 3gAllergy method showed higher sensitivities compared to ImmunoCAP while maintaining specificities of ≥85%.

Both methods showed good agreement with the OFC results, suggesting that they can be valuable tools in the diagnostic process when used alongside clinical history and other tests.

Significance of the Findings

Improved Diagnostic Accuracy

The study demonstrated that the IMMULITE 2000 3gAllergy method had higher sensitivity and comparable specificity to the ImmunoCAP method. This suggests that 3gAllergy may be more effective in identifying true positive cases of CMA, which is important for accurate diagnosis and management of the allergy.

The study also assessed the importance of detecting low levels of specific IgE (sIgE) down to 0.1 kU/L. It found that low-level detection could improve the identification of individuals with allergies, highlighting the clinical significance of even small amounts of sIgE in diagnosing CMA.

Clinical Implications

Although the in vitro diagnostic tools could not entirely replace the OFC, the study showed that these diagnostic methods can help healthcare providers better select patients who truly need to undergo the OFC. This helps to reduce the number of unnecessary and potentially risky challenges. 

This is particularly important given the time-consuming nature and potential severe reactions associated with OFC. The findings suggest that practitioners should consider both clinical history and low levels of sIgE when diagnosing CMA. This combined approach can lead to more accurate diagnoses and better management of the allergy, ultimately improving patient outcomes.

How to Order the Food Allergy IgE Panel

The Food Allergy IgE panel by Empire City Laboratories utilizes the Siemens IgE 3g Allergy method to identify specific IgE antibodies related to common food allergens. This test is instrumental in diagnosing food allergies and assists in tailoring dietary plans to avoid allergic reactions. 

This test, as well as others from Empire City Laboratories, are available on Rupa Health.

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Key Takeaways

• The study found that the IMMULITE 2000 3gAllergy method demonstrated higher sensitivity and comparable specificity to the ImmunoCAP method for diagnosing cow's milk allergy (CMA) in infants.
• Detecting low levels of specific IgE (down to 0.1 kU/L) can enhance the identification of individuals with allergies, emphasizing the clinical importance of even small amounts of sIgE in diagnosing CMA.
• The use of specific IgE measurement methods alongside clinical history can help healthcare providers better select patients for the Oral Food Challenge, reducing unnecessary and risky procedures while improving diagnostic accuracy and patient management.
• This highly accurate technology is available via the Food Allergy IgE panel by Empire City Laboratories