LOINC display name : Normalized silica clotting time (PPP) [Ratio];
LOINC long common name : Normalized silica clotting time of Platelet poor plasma;
LOINC short name : Normalized SCT PPP-Rto;
LOINC description : The Silica Clotting Time (SCT) refers to a version of the activated partial thromboplastin
time (aPTT) in which: 1) 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.;
Has component