Brand Paul L P, Landzaat-Berghuizen Marlouk A
Princess Amalia Children's Centre, Isala Hospital, Zwolle, The Netherlands; UMCG Postgraduate School of Medicine, University Medical Centre and University of Groningen, Groningen, The Netherlands.
Pediatr Allergy Immunol. 2014 Dec;25(8):755-9. doi: 10.1111/pai.12313.
Interpretation of double-blind placebo-controlled food challenges (DBPCFC) can be difficult, particularly with ambiguous subjective symptoms. Early opening of the challenge key (which day is verum and which placebo) may influence the clinician's interpretation of the DBPCFC result.
Fifty-one clinicians reviewing results of 19 DBPCFCs with ambiguous clinical symptoms were randomized into a key first strategy (opening the DBPCFC key before reviewing the symptoms on both challenge days and deciding on the DBPCFC result) or a symptoms first strategy (reviewing symptoms and interpreting both test days as positive or negative before opening the key and deciding on the DBPCFC result).
The proportion of DBPCFCs considered inconclusive was comparable between the two strategy groups (p = 0.791). Participants in the symptoms first group were more likely to consider a DBPCFC as positive (in 14 tests, 73.7%) than subjects in the key first group (four tests, 21.1%). The number of positive tests was higher in the symptoms first group (median 50.0%, interquartile range [IQR] 23.1-76.9%) than in the key first groups (44.0%, IQR 12.0-68.0%, p = 0.031). This was independent of the participant's profession (pediatrician or other), age, gender, or years of experience (p > 0.3).
Clinicians differ in their interpretation of DBPCFC results when symptoms are ambiguous. Opening the key of a DBPCFC before reviewing and interpreting symptoms significantly reduces the likelihood of the challenge being interpreted as positive. Guidelines for performing DBPCFCs should standardize the moment of opening the challenge key.
双盲安慰剂对照食物激发试验（DBPCFC）的结果解读可能存在困难，尤其是对于模糊的主观症状。提前打开激发试验的密钥（哪一天是受试物，哪一天是安慰剂）可能会影响临床医生对DBPCFC结果的解读。
51名临床医生对19项具有模糊临床症状的DBPCFC结果进行评估，他们被随机分为先看密钥策略组（在查看两天激发试验的症状并确定DBPCFC结果之前打开DBPCFC密钥）或先看症状策略组（在打开密钥并确定DBPCFC结果之前查看症状并将两天的试验结果解读为阳性或阴性）。
两组策略中被认为无法得出结论的DBPCFC比例相当（p = 0.791）。先看症状组的参与者比先看密钥组的参与者更有可能将DBPCFC判定为阳性（14项试验中占73.7%）（4项试验中占21.1%）。先看症状组的阳性试验数量高于先看密钥组（中位数为50.0%，四分位间距[IQR]为23.1 - 76.9%）（44.0%，IQR为12.0 - 68.0%，p = 0.031）。这与参与者的职业（儿科医生或其他）、年龄、性别或经验年限无关（p > 0.3）。
当症状模糊时，临床医生对DBPCFC结果的解读存在差异。在查看和解读症状之前打开DBPCFC的密钥会显著降低激发试验被判定为阳性的可能性。进行DBPCFC的指南应规范打开激发试验密钥的时机。
