PTT Test Cost and Medicare Coverage (CPT 85730)

Also called: aPTT · activated partial thromboplastin time · PTT blood test · partial thromboplastin time, activated — all the same test, CPT 85730.

The short answer

Covered when there is a clotting question to answer. Medicare’s national policy (NCD 190.16, the same in every state) covers the PTT for monitoring heparin, for signs of abnormal bleeding or clotting, for conditions known to affect clotting such as liver disease, hemophilia, lupus anticoagulant, or a past clot, and before a procedure when you have a bleeding history or take heparin.

Two things in that policy trip people up. The PTT is not the warfarin test; that is the PT/INR, and the policy says the PTT is not useful for routine warfarin monitoring. And when both PT and PTT appear on an order, the policy says each has to be justified on its own: except while a patient is being switched between heparin and warfarin, both are “not necessary together” just to check an anticoagulant.

When Medicare DOES cover it

The national policy lists four situations. In plain English:

• Heparin monitoring. The PTT’s most common use is to measure the effect of unfractionated heparin and set the dose. Repeats are covered as the dose or the condition changes; the policy sets no numeric limit.
• Signs or symptoms of bleeding or clotting: abnormal bleeding, a hemorrhage or hematoma, small skin bleeds (petechiae) or other signs of a low platelet count, or a swollen arm or leg with or without an injury.
• A condition known to affect the clotting system, inherited or acquired. The policy’s examples include hemophilia, von Willebrand disease, fibrinogen disorders, acute or chronic liver disease (including Wilson’s disease), infections and sepsis, disseminated intravascular coagulation, lupus and other conditions with circulating inhibitors such as a lupus-like anticoagulant, arterial or venous clots and hypercoagulable states, kidney failure or nephrosis, and other bleeding or clotting disorders.
• Before a procedure with a bleeding or clotting risk, when you have a personal or family history of bleeding or you are on heparin.

The diagnosis code list behind this policy is long, about 6,300 codes. If one of these situations genuinely describes yours, the diagnosis for it belongs on your doctor’s order, and coverage follows.

When Medicare does NOT cover it

• Routine warfarin monitoring. The policy says the PTT is not useful for that; the PT/INR is. A PTT on a warfarin patient is covered only while heparin is being stopped or when the PT is far out of range from too much warfarin.
• A routine pre-surgery check with no bleeding history. The policy is direct: testing before a procedure is medically necessary only when there are signs or symptoms of a bleeding or clotting problem, or a personal history of one. A hospital or clinic rule that “everyone gets a PTT before surgery” does not, by itself, make it covered.
• PT and PTT together to check one anticoagulant. Outside the heparin-to-warfarin transition, the policy expects one or the other, and each must be justified separately.

(Never ask anyone to change a code just to get coverage; that is fraud. But doctors often have a legitimate reason for the test that simply wasn’t written down.)

What you pay if it IS covered: $0

Covered lab tests cost Medicare patients nothing, with no deductible and no 20% coinsurance. Medicare pays the lab $6.01 for a PTT, and you owe zero.

What you pay if it is NOT covered, read this before you sign

Quest’s own test directory flags the PTT as “subject to a Medicare Limited Coverage Policy” that “may require a signed ABN when ordering.” If a PTT is on your order without a qualifying reason, most often as a routine pre-surgery check, expect the Advance Beneficiary Notice (ABN), the signature pad, committing you to the lab’s own billing rates if Medicare denies the claim. Before you sign:

1. Ask the lab to print exactly what you would owe. You’re entitled to see the number in black and white first. For perspective: when Medicare covers this exact test, it pays the lab $6.01.
2. Know the direct prices: a PTT sells for $10 at Jason Health (jasonhealth.com, plus their flat $18 lab-collection fee per order, so $28 all in), and both Jason Health and Ulta sell PT/INR and PTT together for a few dollars more. The full table is above. Quest’s and Labcorp’s consumer sites sell the PT/INR but not the PTT. Same certified labs, same blood draw. A PTT is one of the cheapest tests a lab runs, so a large ABN figure for it deserves a question.

Before you sign the pad, 60-second checklist

1. Ask: “Can you print what I’ll owe if Medicare doesn’t pay?”
2. Ask your doctor: “Is this for my heparin, a bleeding or clotting symptom, or a condition I have, or is it a routine pre-op check?” The routine check is the one Medicare’s policy does not cover on its own.
3. Compare the printed price to the direct-purchase prices before deciding how to proceed.

What counts as a “normal” PTT

Start with the range printed on your own report. The PTT is reported in seconds, and published ranges agree closely but not exactly.

• The MedlinePlus Medical Encyclopedia says “in general, the PTT should be 25 to 35 seconds,” that clotting takes longer on blood thinners, and that “normal value ranges may vary slightly among different labs.”
• Cleveland Clinic gives the same 25 to 35 seconds and says it “may vary a bit from lab to lab.”
• Labcorp’s reference interval for people over 16 is 23 to 34 seconds.

There is no treatment target for the PTT in the sources we checked, the way there is an INR target for warfarin. For heparin, the dose is adjusted by the doctor against the hospital’s own PTT scale, which is another reason the number on your report needs their reading.

(Where lab ranges and “optimal” ranges come from, and who decides.)

This page can tell you where those numbers came from. It cannot tell you what yours means; that reading belongs to your doctor, alongside your history and your other results.

Quick questions people ask

What is a PTT test? A blood test that measures, in seconds, how long your blood takes to clot through one part of the clotting system (the “intrinsic pathway,” which includes clotting factors VIII, IX, XI, and XII). A longer time can point to a missing or blocked clotting factor, liver disease, vitamin K deficiency, or heparin; a shorter time is less common. On billing paperwork it is CPT code 85730.

What is the difference between PT and PTT? They check different parts of the clotting system. The PT (reported as INR) is the warfarin test; the PTT is the heparin test, and the one for the inherited bleeding disorders. Labs often run both for a bleeding workup, and MedlinePlus says the PT is the test most commonly ordered alongside a PTT. Medicare’s policy is fine with that for a workup, but for monitoring one blood thinner it expects one test, not two. More on the PT/INR.

Do you have to fast for a PTT test? No. MedlinePlus, Cleveland Clinic, and Quest all list no special preparation. Tell your doctor about every medicine and herbal product you take, since some affect the result, and do not stop any medicine on your own.

How long does a PTT test take? The draw takes minutes. The sample has to be tested within a day (Labcorp lists a one-day turnaround), so results are usually back the same day or the next.

Sources and data dates

Medicare payment amount: CMS Clinical Laboratory Fee Schedule, 2026 Q3 file (national rate). Coverage rules: CMS Medicare Coverage Database, NCD 190.16 (Partial Thromboplastin Time), a national policy identical in every state, and the same text in the NCD Manual, Chapter 1, Part 3. Test descriptions and ranges: MedlinePlus (lab-tests page and Medical Encyclopedia), Cleveland Clinic, Quest test 763, Labcorp test 005207. Consumer prices checked September 2026. Information current as of the date shown above; coverage is always determined by Medicare when your claim is processed.

ClaraCover provides information, not medical, billing, or insurance advice. Talk to your doctor about what tests you need.