Date: September 20, 2016
Re: Specimen Labeling
Effective immediately, test for the specimens without proper identification will be put on hold in order to comply with CLIA Standard 493.103. For the health and safety of your patient’s, American Bio-Clinical Laboratories requires that all specimens submitted for testing must be properly identified. Please insure that the patient’s full name (First and Last Name “initials are not acceptable“) on all blood collection tubes and containers. Histology and Cytology samples will be rejected and returned to the Provider’s office. Due to necessary legal constraints and ramifications regarding patient identification, requisitions and specimens lacking proper identification will remain on “HOLD” status unless the doctor’s office transmit a fax containing a complete explanation as to why the names are different and signed by authorized personnel. Upholding this regulation will safeguard your patient’s and expedite you patient’s test results.
Date: October 6, 2016
Prothrombin Time (PT) and INR
Different preparations of Prothrombin Time reagent will have very different seconds of activity. The INR is the value that equates the seconds to a value that is consistent from different preparations.
At ABC Laboratories we are changing the reagent from our manufacturer to a recombinant human tissue factor (RTF) preparation that is more consistent between lot preparations and is formulated to be insensitive to therapeutic levels of heparin.
Formula for INR: (patient PT/mean normal PT)ISI
The ISI is determined by the manufacturer based upon a standardized preparation; the International Reference Thromboplastin.
The obvious difference with the recombinant human tissue factor (RTF) reagent will be longer seconds from our previous reagent, which makes the new reagent more sensitive, but the INR will be the result you should follow. A more sensitive reagent has a lower ISI.
|ISI:||1.2||Patient time:||18.0 sec||Mean normal PT:||12.0 sec||INR:||1.60|
|ISI:||2.0||Patient time:||18.0 sec||Mean normal PT:||12.0 sec||INR:||2.25|
|ISI:||1.2||Patient time:||23.5 sec||Mean normal PT:||12.0 sec||INR:||2.24|
From the above example, if your patient had an 18.0 second Prothrombin time and the ISI was 2.0, the patient time would be closer to 23.5 seconds for a preparation with an ISI of 1.2; but the INR’s are the same.
At ABC Laboratories we will be implementing the RTF reagent that has an ISI of 1.06. Our retired reagent had an ISI of 1.82. The take-a-way is, the seconds will be longer, but the INR should be the same if there is no change in therapy.
If you have any question, please call Paul Hoyt, Operations Manager, at 323-222-6688.