The effects of different sampling techniques on peripheral post mortem tryptase levels: a recommended sampling method

• Published in: International journal of legal medicine Vol. 133; no. 5; pp. 1477 - 1483
• Main Authors: Garland, J., Philcox, W., McCarthy, S., Hensby-Bennet, S., Ondruschka, B., Woydt, L., Da Broi, U., Palmiere, C., Lam, L., Ahn, Y., Kesha, K., Stables, S., Tse, R.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.09.2019; Springer Nature B.V
• Subjects: Adult; Aged; Aged, 80 and over; Anaphylaxis; Autopsy - methods; Blood; Blood Specimen Collection - methods; Constriction; Female; Femoral Artery; Femoral Vein; Forensic Medicine; Forensic pathology; Forensic Pathology - methods; Humans; Male; Medical Law; Medicine & Public Health; Method Paper; Middle Aged; Outliers (statistics); Prospective Studies; Sampling methods; Sampling techniques; Statistical methods; Tryptases - blood; Young Adult; Anaphylaxis; Post mortem; Tryptase; Sampling; Venous; Arterial; Cutdown; Aspirate
• ISSN: 0937-9827; 1437-1596
• DOI: 10.1007/s00414-019-02038-9

Different sampling techniques can impact on post mortem tryptase levels. A previous study demonstrated significantly lower femoral post mortem total tryptase levels in samples collected via transcutaneous aspiration compared with directly sampling during internal examination. However, an outlier with high tryptase level was noted in one transcutaneous aspiration sample. This 6-month prospective study compared total post mortem tryptase levels between 21 paired aspirated venous and arterial femoral blood samples, and 19 paired aspirated and cutdown femoral venous blood samples in non-anaphylactic deaths only. No statistical differences were demonstrated between the different sampling methods. However, four outlier cases with higher tryptase levels in aspirated arterial and femoral cutdown samples compared with aspirated venous femoral samples were noted. The reasons for the outliers may be due to the bloods collected from these two methods being contaminated by central arterial and venous blood with high tryptase levels respectively. None of the aspirated venous femoral post mortem tryptase levels were above recognized post mortem tryptase cutoff to diagnose anaphylaxis. This study recommends aspirating blood samples from a clamped femoral/external iliac vein for post mortem tryptase analysis should be defined as the gold standard. Further study using the recommended sampling method on post mortem tryptase levels in non-anaphylactic and anaphylactic cases is warranted.