This week's question was, "How long do you require patients or controls to go without aspirin before platelet aggregometry?"
The answers are below...

The PT delta-check question was...

Please select the 24-hour PT delta-check range closest to the one you use.

The answers...

Here are the results of our March 18, 2009 quick question:

What do you use as a delta-check method for the prothrombin time test?

a. INR: 17 (34%)
b, PT in seconds: 7 (14%)
c. Combination of INR and seconds: 13 (26%)
d. No delta-check: 13 (26%)

This is a relatively even distribution. Let's next find out what ranges we are using.

Here are the results of our 2-16-09 D-dimer assay question:

"What method do you use to measure D-dimer for the purpose of ruling out deep venous thrombosis or pulmonary embolism?

Answers...

Here is a summary of our Quick Question about D-dimer reporting units:

Part 1: Based on Dr. Olson's guest blog posted last July, D-dimer test results suffer from a variety of confusing reporting methods. What units do you used to report your D-dimer results?
a. D-dimer units: 8 (67%)
b. Fibrinogen equivalent units: 4 (33%)

Part 2: What concentration units do you use?
a. ng/mL: 6 (46%)
b. ug/mL: 5 (38%)
c. mg/dL: 0
d. mg/L: 2 (15%)

The results of our December 20 Quick Question are a little surprising:

How do you produce your PTT therapeutic range for monitoring unfractionated heparin?

a. Spike a normal plasma with measured heparin and perform PTTs: 6 (32%)
b. Use 1.5 to 2.5 X the mean of normal: 1 (5%)
c. Brill-Edwards ex-vivo curve using anti-Xa as the reference: 9 (47%)
d. We use the anti-Xa for assay for all heparin monitoring: 3 (16%)

Comments appear below...

Here is the result of this week's Quick Question. We asked, According to CLSI, we reduce the anticoagulant to blood ratio for coagulation testing draws when the hematocrit is over 55%. Assuming you know the hematocrit in advance, how do you manage this?

Your answers...

Here is a note I posted 11/16/07 under the heading, "Why All the PTTs?"

It seems that many North American institutions are moving more and more to the use of low molecular weight heparin (mostly Lovenox in the US) and pentasaccharide (Fondaparinux, Arixtra) in place of standard unfractionated heparin. Yet, the lab volume of partial thromboplastin time (PTT, APTT) tests seems to be holding steady. What are all those PTTs for if we are no longer monitoring heparin? And, shouldn't the volume of anti-Xa heparin assays be increasing?

More...

In response to a question from Kim Kinney we posted the following "Quick Question" last week, "What is your critical INR call-out number?" The answers were relatively predictable...

Our current "quick question" was provided by Dr. Michael Blechner:

"When performing ELISA testing for heparin-induced thrombocytopenia (HIT), how do you report the results?

Answers from twenty reponses are below...