What does this LOINC code represent?

This LOINC code identifies a lab observation, measurement, question, or clinical concept in a standardized format.

Is this enough to understand my test result?

No. The code identifies the test or observation, but the interpretation depends on the actual result, reference range, and clinical context.

LOINCActiveBoth

LOINC Code 66736-0: Normalized silica clotting time (PPP) [Ratio]

Name: LOINC Code 66736-0: Normalized silica clotting time (PPP) [Ratio]
Creator: HealthAssure Clinical Team
Published: 2026-05-21T08:59:46.212Z

66736-0 is a LOINC code used to identify Normalized silica clotting time (PPP) [Ratio] in laboratory and clinical observation data. You may see this code in lab systems, lab reports, EHR exports, interoperability feeds, or other structured clinical data exchanges. LOINC codes identify tests, measurements, observations, survey items, and clinical questions in a standardized way. It is associated with the component Normalized silica clotting time. It is commonly used with the system or sample type PPP.

Reviewed by HealthAssure Clinical TeamUpdated 21 May 2026

What is this code?

LOINC codes identify tests, measurements, observations, survey items, and clinical questions in a standardized way. It is associated with the component Normalized silica clotting time. It is commonly used with the system or sample type PPP.

When is it used?

Used in lab systems, EHRs, and clinical data exchange.
May identify a test, observation, survey item, or clinical document request rather than a diagnosis.
Status: ACTIVE
Order vs observation: Both

What it does not mean

The code identifies the observation or test, not the actual result.

Key facts

Normalized silica clotting time of Platelet poor plasma

Normalized silica clotting time

The Silica Clotting Time (SCT) refers to a version of the activated partial thromboplastin time (aPTT) in which1) silica replace kaolin as activator in order to make the test amenable to automation (since kaolin is opaque) and 2) there is a screening reagent with very low phospholipid concentration, diminished compared to the standard aPTT reagent, to maximize sensitivity to lupus anticoagulant (LAC) and 3) there is a confirmatory reagent which uses excess phospholipid in an attempt to neutralize the putative LAC. (Original reference: Chantarangkul et al., Silica Clotting Time (SCT) as a Screening and Confirmatory Test Detection of the Lupus Anticoagulants. 1992. Thrombosis Research 67:355-365.) The normalize SCT ratio is calculated as follows: (Patient Screen Result in seconds / Mean Normal Screen Result in seconds) / (Patient Confirm Result in seconds / Mean Normal Confirm Result in seconds). The prototype test described by this code is the HemosIL(TM) Silica CLotting Time test. LabCorp performs a test similar to the screening step called "Partial Thromboplastin Time (PTT), Lupus Anticoagulant" (LabCorp #117002) which also uses silica and diminished PL, but apparently they do not report it as a normalized ratio.

Clot; Clot tm; Clottable; COAGULATION; Coagulation time; Hematology; Heme; Normalized SCT; Plas; Platelet poor plasma; Point in time; QNT; Quan; Quant; Quantitative; Random; Rate; Ratios; R-time; Rto; SCT; Silicon dioxide

Where you may see this code

You may see this code in lab systems, lab reports, EHR exports, interoperability feeds, or other structured clinical data exchanges.

Common synonyms

Normalized silica clotting time (PPP) [Ratio]Normalized silica clotting time of Platelet poor plasmaNormalized SCT PPP-RtoNormalized silica clotting timeCOAGNormalized silica clotting time, BloodRatio

Frequently asked questions

Code details

Code66736-0

SystemLOINC

Display nameNormalized silica clotting time (PPP) [Ratio]

DescriptionNormalized silica clotting time

Short nameNormalized SCT PPP-Rto

ComponentNormalized silica clotting time

PropertyRatio

TimingPt

System (specimen)PPP

ScaleQn

ClassCOAG

StatusACTIVE

Order/ObservationBoth

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released2.38

Last changed2.73

Consumer names

Normalized silica clotting time, Blood

Part names

Normalized silica clotting timeRatioPtPPPQnPoint in time (spot)Platelet poor plasma

About this content

This page is prepared by HealthAssure's clinical team using official coding standards from LOINC. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.