Negative Predictive Value Of Skin Tests Research Articles

Management of Beta-Lactam Antibiotics Allergy: A Real-Life Study.

Beta-lactam allergy is a common problem in everyday medical practice and is recognized as a major public health issue. Carrying this label frequently leads to the avoidance of all beta-lactam antibiotics, favoring the use of other less preferred classes of antibiotics, that are more expensive and associated with more side effects and increased antimicrobial resistance. Therefore, delabeling a beta-lactam allergy is part of antimicrobial stewardship programs. Herein, we retrospectively examined the clinical records of 576 patients who were referred to our center for a label of allergy to beta-lactam antibiotics and were systematically investigated following a standardized algorithm. Our main aim was to evaluate the frequency of confirmed immediate- and delayed-type allergy to commonly prescribed subclasses of beta-lactam antibiotics (penicillin and cephalosporin), as well as the negative predictive value (NPV) and the sensitivity of skin tests. Our secondary aims were to examine the safety of beta-lactam skin testing and drug challenge. We identified that 260 patients reported a history of immediate reactions, 131 of delayed reactions, and 114 of unknown timing or mechanism of reactions. Following assessment and testing, 86 (18.3%) patients had a confirmed allergy to any beta-lactam antibiotics; 63 (13.4%) with an immediate- and 23 (4.9%) with a delayed-type reaction. Most frequently identified confirmed allergy was to penicillins (65 patients), followed by cephalosporins (21 patients). When immediate-type reactions were examined, NPV of skin tests were 96.3% and 100% for penicillins and cephalosporins, respectively. When delayed reactions were considered, NPV were 91.9 and 87.5% for penicillins and cephalosporins, respectively. Evaluation of the safety of skin tests according to the standardized procedure showed that systemic allergic reactions occurred in only 0.7% of skin tests and in 3.1% of drug challenges. Overall, our data indicate that only 18.3% of patients with a beta-lactam allergy label have a confirmed allergy and non-allergic patients can be safely delabeled through allergic workup based on skin tests and drug challenge. This approach supports the policy of saving second-line antibiotics through a standardized allergy workup.

Allergy Evaluation of Hypersensitivity to Platinum Salts and Taxanes: A Six-Year Experience

Hypersensitivity reactions (HSRs) to platinum salts (PS) and taxanes (TX) are a challenge to cancer management. Allergy evaluation based on skin tests (ST) and graded challenges can provide a diagnosis of an allergy to a suspected drug and indicate possible treatment with alternative same-class drugs. This study aimed to estimate the negative predictive value of ST in the diagnosis of HSRs to TX and PS. This multicenter study prospectively enrolled patients with a suspected HSR to PS and TX. ST were performed for chemotherapy, drugs of the same pharmacological class, and other agents (latex or cotreatments). For patients with negative ST, a graded challenge was performed by the cancer teams trained in allergy management. A total of 119 consecutive patients were included during a 6-year period. ST results were positive for 58% of the cohort: for TX in 7 patients and for PS in 62 patients. Other agents were responsible for 4.2% of cases. Skin cross-reactivity was 50% for TX and 30% for PS. A graded challenge was performed in 14 patients for TX and in 50 patients for PS. Negative predictive values (NPVs) for ST were 100% for TX and 92% for PS, with NPVs for individuals PS of 100% for cisplatin, 89% for oxaliplatin, and 87% for carboplatin. ST to PS or TX offered a high NPV, making allergy evaluation a key element in the management of patients with cancer. Graded challenges can be safely performed by oncology teams trained in anaphylaxis management.

Skin testing only with penicillin G in children with a history of penicillin allergy

BackgroundThe absence of commercially available penicilloyl-polylysine (PPL) for most of the last decade severely hampered the practice of penicillin allergy evaluation because skin testing without PPL is reported to have a poor negative predictive value (NPV). ObjectiveTo determine the safety and NPV of skin testing without PPL using only penicillin G followed by a 3-dose graded challenge to the incriminated penicillin in children with a history of penicillin allergy. MethodsPatients evaluated for a history of penicillin allergy at the CHU Sainte-Justine Allergy Clinic between December 2006 and December 2009 were skin tested only with penicillin G and underwent a 3-dose graded challenge to the culprit penicillin if the skin test result was negative. ResultsAmong 563 patients skin tested to penicillin G, 185 (33%) had a positive skin test result. These patients had a shorter interval between the initial reaction and skin testing compared with patients with a negative skin test result (P = .03). A total of 375 of 378 patients (99%) with a negative skin test result were challenged and 18 (4.8%) reacted, translating into a NPV of 95.2% (95% confidence interval [CI], 92.5%–97.1%). Three of 17 patients with a history of anaphylaxis and a negative skin test result reacted to challenge (NPV, 82.4%; 95% CI, 59.0–93.8%). All challenge reactions were mild and resolved promptly with treatment. ConclusionAmong children with a history of penicillin allergy, skin testing only with penicillin G followed by a 3-dose graded challenge to the incriminated penicillin is safe and yields a good NPV. This approach could be useful when PPL is unavailable.

Clinical Value Of a Negative Skin Test To Contrast Radio Media (CR) In Further Exposures

Adverse reactions after administration of radiocontrast (RC) are common and can be caused by toxicity of their components or mediated by the immune system. Recent studies highlight the involvement of immune system reactions after RC using. Skin testing (ST) has shown a good clinical value in hypersensitivity reactions, helping the diagnosis of IgE -mediated mechanisms, and lymphocytes mediated reactions (delayed reactions). The objective is to demonstrate the negative predictive value of ST in performing safety procedures with administration of RC.

The impact of penicillin skin testing on clinical practice and antimicrobial stewardship

Penicillin skin testing (PST) is a simple and reliable way of diagnosing penicillin allergy. After being off the market for 4 years, penicilloyl-polylysine was reintroduced in 2009 as PRE-PEN. We describe the negative predictive value (NPV) of PST and the impact on antibiotic selection in a sample of hospitalized patients with a reported history of penicillin allergy. We introduced a quality improvement process at our 861-bed tertiary care hospital that used PST to guide antibiotic usage in patients with a history consistent with an immunoglobulin E (IgE)-mediated reaction to penicillin. Subjects with a negative PST were then transitioned to a β-lactam agent for the remainder of their therapy. NPV of skin testing was established at 24-hour follow-up. We are reporting the result of 146 patients tested between March 2012 and July 2012. A total of 146 patients with a history of penicillin allergy and negative PST were treated with β-lactam antibiotics. Of these, only 1 subject experienced an allergic reaction to the PST. The remaining 145 patients tolerated a full course of β-lactam therapy without an allergic response, giving the PST a 100% NPV. We estimated that PST-guided antibiotic alteration for these patients resulted in an estimated annual savings of $82,000. Patients with a history of penicillin allergy who have a negative PST result are at a low risk of developing an immediate-type hypersensitivity reaction to β-lactam antibiotics. The increased use of PST may help improve antibiotic stewardship in the hospital setting.