How Pre-Analytical Factors Affect Blood Culture Diagnostic Accuracy in Adult Inpatients: A Cross-Sectional Analysis

Abstract

Background and Purpose: Blood culture (BC) remains the gold standard for detecting bloodstream infections. Given the typically low microbial load in adult bacteremia, both the volume of blood sampled and proper collection techniques are essential for diagnostic accuracy. This study aimed to evaluate BC collection practices in adult patients, focusing on blood volume adequacy, departmental variation, and the influence of pre-analytical factors on culture yield. Material and Methods: This retrospective study included all aerobic and anaerobic BC bottles submitted from adult patients to the Microbiology Laboratory of XXX University Faculty of Medicine between January 10 and April 30, 2022. Blood volume per bottle was visually measured post-incubation. Demographic and clinical data were extracted from hospital records. Results: A total of 4695 BC bottles representing 1463 episodes from 712 adult patients were analyzed. Only 47% of episodes met the recommended standard of at least two sets per episode. About one-fourth of bottles were optimally filled, with overfilling more prevalent than underfilling. Overfilling was paradoxically associated with lower positivity rates. Patients with malignancy had significantly higher blood volumes, while those with neuropsychiatric conditions or recent surgery had lower volumes. Blood volumes were substantially lower in the ICU and emergency departments. Central venous catheter use was associated with higher but not necessarily optimal blood volumes. Conclusion: Suboptimal adherence to BC sampling standards, particularly in blood volume and set number, persists across clinical settings. Interventions targeting pre-analytical errors and departmental differences may improve diagnostic yield in suspected bloodstream infections.

Keywords

• Blood culture
• blood volume
• pre-analytical factors
• diagnostic microbiology
• central venous catheter

Preanalitik Faktörler, Yetişkin Yatan Hastalarda Kan Kültürü Tanı Doğruluğunu Nasıl Etkiler? : Kesitsel Bir Analiz

Abstract

Amaç: Kan kültürü (KK), kan dolaşımı enfeksiyonlarının tespitinde altın standart olmaya devam etmektedir. Yetişkin bakteremisinde genellikle düşük mikrobiyal yük göz önüne alındığında, hem örneklenen kan hacmi hem de doğru örnekleme teknikleri tanı doğruluğu için önemlidir. Bu çalışma, yetişkin hastalarda KK toplama uygulamalarını değerlendirmeyi, kan hacmi yeterliliğini, departman çeşitliliğini ve kültür verimi üzerindeki preanalitik faktörlerin etkisini incelemeyi amaçlamıştır. Gereç ve Yöntem: Bu retrospektif çalışma, 10 Ocak - 30 Nisan 2022 tarihleri arasında yetişkin hastalardan XXX Üniversitesi Tıp Fakültesi Mikrobiyoloji Laboratuvarı'na gönderilen tüm aerobik ve anaerobik KK şişelerini kapsamıştır. Şişe başına kan hacmi inkübasyon sonrası görsel olarak ölçülmüştür. Demografik ve klinik veriler hastane kayıtlarından elde edilmiştir. Sonuçlar: 712 yetişkin hastadan alınan, 1463 sepsis atağını temsil eden toplam 4695 KK şişesi analiz edilmiştir. Atakların yalnızca %47'si, atak başına en az iki setlik önerilen standardı karşılamıştır. Şişelerin yaklaşık dörtte biri optimum düzeyde doldurulmuş ve aşırı dolum, yetersiz dolumdan daha yaygındı. Aşırı dolum, paradoksal olarak daha düşük pozitiflik oranlarıyla ilişkilendirildi. Malignitesi olan hastalarda kan hacimleri önemli ölçüde daha yüksekken, nöropsikiyatrik rahatsızlığı olan veya yakın zamanda ameliyat geçirmiş hastalarda kan hacimleri daha düşüktü. Yoğun bakım ve acil servislerde kan hacimleri önemli ölçüde daha düşüktü. Santral venöz kateter kullanımı, daha yüksek ancak mutlaka optimum olmayan kan hacimleriyle ilişkiliydi. Tartışma: Özellikle kan hacmi ve set sayısı açısından, meme kanseri örnekleme standartlarına yetersiz uyum, klinik ortamlarda devam etmektedir. Analiz öncesi hataları ve departman farklılıklarını hedef alan müdahaleler, şüpheli kan dolaşımı enfeksiyonlarında tanısal verimi artırabilir.

Keywords

• Kan kültürü
• kan hacmi
• preanalitik faktörler
• tanısal mikrobiyoloji
• santral venöz kateter

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