Don't be guided purely by numbers : false increased TSH values due to analytical interference

BACKGROUND: Physicians are often guided by laboratory values. When a clinical presentation does not match laboratory values, one must consider the possibility that these values may be falsely increased or decreased. A common cause is analytical interference.

CASE DESCRIPTION: A 57-year-old male, presenting with fatigue and palpitations, had high TSH and normal FT4 values. Although there were no fitting clinical symptoms for these values, the patient was treated with levothyroxine assuming he had subclinical hypothyroidism. TSH levels remained high, however, whereas FT4 levels increased and the patient developed thyrotoxicosis. Eventually, it was discovered that the TSH was falsely elevated.

CONCLUSION: The patient turned out to have macro TSH, where TSH forms conjunctions with IgG into larger molecules. These conjugates cause a rarely occurring interference during laboratory analysis, resulting in a falsely increased TSH value.

Medienart:

E-Artikel

Erscheinungsjahr:

2020

Erschienen:

2020

Enthalten in:

Zur Gesamtaufnahme - volume:164

Enthalten in:

Nederlands tijdschrift voor geneeskunde - 164(2020) vom: 02. Juli

Sprache:

Niederländisch

Weiterer Titel:

Vaar niet alleen op een getal

Beteiligte Personen:

Tibben, N E [VerfasserIn]
Bons, J A P [VerfasserIn]
van den Berg, S A A [VerfasserIn]
Huisman, J [VerfasserIn]
Krabbe, J G [VerfasserIn]

Themen:

9002-71-5
Case Reports
Immunoglobulin G
Journal Article
Q51BO43MG4
Thyrotropin
Thyroxine

Anmerkungen:

Date Completed 14.12.2020

Date Revised 14.12.2020

published: Electronic

Citation Status MEDLINE

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM313326584