Cardiff University | Prifysgol Caerdydd ORCA
Online Research @ Cardiff 
WelshClear Cookie - decide language by browser settings

Laboratory results - When the figures don’t fit the facts! [Abstract]

Dyas, J., Thomas, A., Krishna, Channarayapatna and Thompson, John Paul 2011. Laboratory results - When the figures don’t fit the facts! [Abstract]. Clinical Toxicology 49 (3) , p. 260. 10.3109/15563650.2011.568269

Full text not available from this repository.


Objective: Information relating to interference in certain biochemistry analyses is readily available in the scientific literature, yet the UK National Poisons Information Service (NPIS) still regularly receives enquiries from clinicians struggling to interpret unexpected results. We report three recent cases that serve to illustrate how erroneous laboratory results can confuse the clinical picture and even lead to misdiagnosis in cases of poisoning. Case series: 1. A 19-year old male presented at hospital claiming a deliberate ingestion of methanol. He appeared clinically well but had a markedly raised serum creatinine - 766 µmol/L. He had been admitted 10 days previously with a paracetamol overdose and it was assumed that the elevated creatinine was a consequence of this and his methanol story was disregarded. An NPIS specialist advised that nitromethane in model engine fuel is known to give falsely high results with certain (Jaffé) creatinine assays. This was confirmed and antidotal treatment was commenced for methanol ingestion. 2. A 35-year old male was admitted with acidosis (pH 6.8) and a raised serum lactate concentration of 24 mmol/L. A preliminary diagnosis of cyanide poisoning was made and antidote considered. An NPIS specialist advised that certain Point of Care blood gas analysers have been reported to provide falsely elevated blood lactate concentrations when ethylene glycol metabolites are present. Blood lactate was measured on a different instrument and shown to be within normal limits. Antidotal therapy was commenced for ethylene glycol ingestion - a diagnosis subsequently confirmed by blood ethylene glycol measurement and a markedly raised osmolar gap. 3. A 3-year old girl was admitted with a 3-day history of vomiting. She was obtunded, acidotic (pH 6.9) and had a serum salicylate concentration of 50 mg/L, although there was no history of aspirin ingestion. Supportive treatment was initiated and a search at home for possible sources of salicylic acid made. A suggestion by NPIS to the clinician that metabolic disorders such as Maple Syrup Urine Disease can cause acidosis and give false positive salicylate results was later confirmed to be the case. Conclusion: The possibility of assay interference should be considered when the figures don’t fit the facts.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Medicine
Subjects: R Medicine > R Medicine (General)
Additional Information: 2011 International Congress of the European Association of Poisons Centres and Clinical Toxicologists, 24-27 May 2011, Dubrovnik, Croatia
Publisher: Taylor & Francis
ISSN: 1556-3650
Last Modified: 19 Oct 2021 01:17

Actions (repository staff only)

Edit Item Edit Item