# Pitfalls in Coagulation Testing: A Pediatric Case of Lupus Anticoagulant Hypoprothrombinemia Syndrome Following Enterocolitis

## TL;DR

A child developed a rare coagulation disorder after an infection, causing misleading lab results and mobility issues.

## Contribution

Highlights diagnostic challenges and pitfalls in coagulation testing due to lupus anticoagulant in pediatric cases.

## Key findings

- Prolonged prothrombin time and APTT were observed in a child with enterocolitis.
- Decreased coagulation factors and inhibitors were detected, leading to a diagnosis of LAHPS.
- LA interference with phospholipid-based tests can cause misinterpretation of coagulation abnormalities.

## Abstract

In children, the lupus anticoagulant (LA) is transiently produced after infection and rarely causes bleeding tendency, known as LA-hypoprothrombinemia syndrome (LAHPS). In this case report, we describe a child presenting with difficulty standing and walking after enterocolitis and complicated false coagulation abnormalities. Prolonged prothrombin time and activated partial thromboplastin time (APTT); decreased factors II, VIII, IX, XI, and XII; and inhibitors for factors VIII and IX were detected. On the basis of such findings as inhibitor pattern in the APTT cross-mixing test and positivity for serum LA, LAHPS was diagnosed. Physicians should be aware of the interference by LA with phospholipid-based coagulation tests, leading to the misinterpretation of the unusual coagulation abnormalities in LAHPS.