Preferred Sample Type

Lipoprotein X (LpX)

Suitable Specimen Types

  • Serum
  • EDTA Whole Blood
  • EDTA Plasma

Specimen Transport

Send sample to referral laboratory by first class post.

Sample Processing in Laboratory

Sample can be sent as either serum/plasma or whole blood.

Turnaround Time

3 Days

Lipoprotein X (LpX)

General Information

Lipoprotein X (LP-X) is an abnormal lipoprotein that appears in the sera of patients with obstructive jaundice and is thus a marker for cholestasis. The presence of LP-X in serum does not allow discrimination between intra- and extra-hepatic cholestasis. In addition LP-X is present in the plasma of patients with familial plasma lecithin: cholesterol acyl transferase (LCAT) deficiency. It is a spherical particle that aggregates strongly. Phospholipids and unesterified cholesterol make up the bulk of LP-X, which is a low density lipoprotein. Protein, cholesterol esters, and triglycerides together make up 12 percent of the composition of LP-X. Lithocholic acid is the major bile acid in LP-X. Three species of LP-X have been isolated (LP-X1, LP-X2 and LP-X3). Because of its aggregating properties, LP-X complexes with enzymes, such as alkaline phosphatase. Electrophoretic and immunochemical methods are available for assay of LP-X. The fact that bile lipoprotein can be converted to LP-X by addition of albumin, and LP-X can be converted to bile lipoprotein by the addition of bile salts may suggest that the integrity of the LPX molecule depends on a certain critical bile salts to albumin ratio. Phospholipase in plasma is implicated in the catabolism of LP-X. The role of LP-X in cholestasis is apparently related to the removal of free cholesterol from the circulation as a consequence of its aggregating properties.

Reference Range

Provided by referral laboratory


  • EQA Scheme?: No

The laboratories at Heartlands Hospital, Good Hope Hospital and Solihull Hospital form part of the services provided by University Hospitals Birmingham and are UKAS (United Kingdom Accreditation Service) accredited to the ISO 15189:2012 standard. For a list of accredited tests and other information please visit the UKAS website using the following link:

  • Heartlands, Good Hope and Solihull Hospital pathology laboratories are a UKAS accredited medical laboratory No.8217
  • United Kingdom Health Security Agency laboratory is a UKAS accredited medical laboratory No.8213

Tests not appearing on the UKAS Schedule of Accreditation currently remain outside of our scope of accreditation. However, these tests have been validated to the same high standard as accredited tests and are performed by the same trained and competent staff.

For further test information, please visit the test database:

Protection of personal information - Laboratory Medicine comply with the Trust Data Protection policy and have procedures in place to allow the Directorate and its employees to comply with the Data Protection act  1998 and associated best practice and guidance.

For further information contact Louise Fallon, Quality Manager, 0121 424 1235