Variability of anti-PF4/heparin antibody results obtained by the rapid testing system ID-H/PF4-PaGIA

Schneiter, S; Colucci, G; Sulzer, I; Barizzi, G; Lämmle, B; Alberio, L (2009). Variability of anti-PF4/heparin antibody results obtained by the rapid testing system ID-H/PF4-PaGIA. Journal of thrombosis and haemostasis, 7(10), pp. 1649-55. Oxford: Wiley-Blackwell 10.1111/j.1538-7836.2009.03507.x

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BACKGROUND: Recent studies have shown that a low clinical pretest probability may be adequate for excluding heparin-induced thrombocytopenia. However, for patients with intermediate or high pretest probability, laboratory testing is essential for confirming or refuting the diagnosis. Rapid assessment of anti-PF4/heparin-antibodies may assist clinical decision-making. OBJECTIVES: To evaluate the performance of rapid ID-H/PF4-PaGIA. In particular, we verified reproducibility of results between plasma and serum specimens, between fresh and frozen samples, and between different ID-H/PF4-polymer lots (polystyrene beads coated with heparin/PF4-complexes). PATIENTS/METHODS: The samples studied were 1376 plasma and 914 corresponding serum samples from patients investigated for suspected heparin-induced thrombocytopenia between January 2000 and October 2008. Anti-PF4/heparin-antibodies were assessed by ID-H/PF4-PaGIA, commercially available ELISAs and heparin-induced platelet aggregation test. RESULTS: Among 914 paired plasma/serum samples we noted discordant results (negative vs. low-titre positive) in nine instances (1%; 95%CI, 0.4-1.6%). Overall, agreement between titres assessed in plasma vs. serum was highly significant (Spearman correlation coefficient, 0.975; P < 0.0001). Forty-seven samples tested both fresh and after freezing/thawing showed a good agreement, with one discordant positive/negative result (Spearman correlation coefficient, 0.970; P < 0.0001). Among 1376 plasma samples we noted a strikingly variable incidence of false negative results (none - 82%; 95%CI, 66-98%), depending on the employed ID-H/PF4-polymer lot. Faulty lots can be recognized by titrating commercial positive controls and stored samples of HIT-patients. CONCLUSION: Laboratories performing the assay should implement stringent internal quality controls in order to recognize potentially faulty ID-H/PF4-polymer lots, thus avoiding false negative results.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Department of Haematology, Oncology, Infectious Diseases, Laboratory Medicine and Hospital Pharmacy (DOLS) > Clinic of Haematology and Central Haematological Laboratory

UniBE Contributor:

Colucci, Giuseppe; Lämmle, Bernhard and Alberio, Lorenzo

ISSN:

1538-7836

Publisher:

Wiley-Blackwell

Language:

English

Submitter:

Factscience Import

Date Deposited:

04 Oct 2013 15:10

Last Modified:

16 Jul 2018 14:18

Publisher DOI:

10.1111/j.1538-7836.2009.03507.x

PubMed ID:

19515091

Web of Science ID:

000270129200007

URI:

https://boris.unibe.ch/id/eprint/30900 (FactScience: 195258)

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