If you need to know which are the prothrombin time reference ranges or you require more information about prothrombin time in a blood test, you can visit normal prothrombin time in a blood test.
A high prothrombin time (PT) in a blood test is a sign of a coagulation disorder. It means that it takes a long time for the blood to form a clot to stop a hemorrhage and therefore there is an excessive bleeding.
Coagulation involves both platelets and proteins (coagulation factors). Coagulation factors are proteins produced by the liver that need vitamin K. Coagulation factors work together in cascade to make a blood clot.
A high prothrombin time (PT) in a blood test may be a sign of:
Prothrombin time (PT) test is also used for monitoring oral anticoagulant therapy (with warfarin or acenocoumarol) in people at a high risk for blood clot formation. It is better for this matter to use the INR (International normalized ratio).
A higher than normal prothrombin time (PT) means:
A mild prothrombin time (PT) increase may be just a consequence of the reagents used to measure this time and it does not have any diagnostic importance.
A visit to your doctor is recommended if you experience any other symptoms like prolonged bleedings. He will decide if additional coagulation tests are required.
A moderate prothrombin time (PT) increase requires a visit to your doctor.
If after vitamin K injection prothrombin time returns to normal range in about 3 days, malabsorption or vitamin K deficiency may be suspected. If not, the inability of the liver to respond to vitamin K, demonstrates that the liver is damaged and it cannot produce more prothrombin and other coagulation factors, even with abundant vitamin K.
Another possibility is disseminated intravascular coagulation (DIC). It comes with low fibrinogen value, platelets lower than normal and a high activated partial thromboplastin time (aPTT) in a blood test.
A marked prothrombin time (PT) increase may be related to a liver disease (hepatitis, cirrhosis) if AST and ALT are also high.
It may be also due to disseminated intravascular coagulation (DIC) in an acute presentation (fibrinogen high, platelets low and activated partial thromboplastin time aPTT high).
In any case, it is necessary a visit to your doctor because a prothrombin time above 30 seconds may cause prolonged bleeding that are difficult to stop.
A severe prothrombin time (PT) increase may be related to a liver failure that can lead to important health disorders.
It is very likely that the liver does not work properly and it is adequate to study the degree of hepatic encephalopathy, the serum creatinine and the arterial pH for a better diagnosis.
There are some health circumstances or drugs than can raise the prothrombin time in a blood test:
The most common diseases why the prothrombin time can be higher than normal are:
If the prothrombin time (PT) value is higher than normal, you may follow the next tips:
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The following values are considered to be above the normal range:
IMPORTANT: These levels are expressed in seconds. They are an example of a healthy man/woman of about 40 years old with no known disease and not taking any medication. The ranges can be different depending on the laboratory or on your personal circumstances.
Prothrombin time | |||||||
|---|---|---|---|---|---|---|---|
| Mild prothrombin time (PT) increase | |||||||
| 13.1 s | 13.2 s | 13.3 s | 13.4 s | 13.5 s | 13.6 s | 13.7 s | 13.8 s |
| 13.9 s | 14 s | 14.1 s | 14.2 s | 14.3 s | 14.4 s | 14.5 s | 14.6 s |
| 14.7 s | 14.8 s | 14.9 s | 15 s | 15.1 s | 15.2 s | 15.3 s | 15.4 s |
| 15.5 s | 15.6 s | 15.7 s | 15.8 s | 15.9 s | 16 s | ||
| Moderate prothrombin time (PT) increase | |||||||
| 16.1 s | 16.2 s | 16.3 s | 16.4 s | 16.5 s | 16.6 s | 16.7 s | 16.8 s |
| 16.9 s | 17 s | 17.1 s | 17.2 s | 17.3 s | 17.4 s | 17.5 s | 17.6 s |
| 17.7 s | 17.8 s | 17.9 s | 18 s | 18.1 s | 18.2 s | 18.3 s | 18.4 s |
| 18.5 s | 18.6 s | 18.7 s | 18.8 s | 18.9 s | 19 s | 19.1 s | 19.2 s |
| 19.3 s | 19.4 s | 19.5 s | 19.6 s | 19.7 s | 19.8 s | 19.9 s | 20 s |
| Marked prothrombin time (PT) increase | |||||||
| 20.1 s | 20.2 s | 20.3 s | 20.4 s | 20.5 s | 20.6 s | 20.7 s | 20.8 s |
| 20.9 s | 21 s | 21.1 s | 21.2 s | 21.3 s | 21.4 s | 21.5 s | 21.6 s |
| 21.7 s | 21.8 s | 21.9 s | 22 s | 22.1 s | 22.2 s | 22.3 s | 22.4 s |
| 22.5 s | 22.6 s | 22.7 s | 22.8 s | 22.9 s | 23 s | 23.1 s | 23.2 s |
| 23.3 s | 23.4 s | 23.5 s | 23.6 s | 23.7 s | 23.8 s | 23.9 s | 24 s |
| 24.1 s | 24.2 s | 24.3 s | 24.4 s | 24.5 s | 24.6 s | 24.7 s | 24.8 s |
| 24.9 s | 25 s | 25.1 s | 25.2 s | 25.3 s | 25.4 s | 25.5 s | 25.6 s |
| 25.7 s | 25.8 s | 25.9 s | 26 s | 26.1 s | 26.2 s | 26.3 s | 26.4 s |
| 26.5 s | 26.6 s | 26.7 s | 26.8 s | 26.9 s | 27 s | 27.1 s | 27.2 s |
| 27.3 s | 27.4 s | 27.5 s | 27.6 s | 27.7 s | 27.8 s | 27.9 s | 28 s |
| 28.1 s | 28.2 s | 28.3 s | 28.4 s | 28.5 s | 28.6 s | 28.7 s | 28.8 s |
| 28.9 s | 29 s | 29.1 s | 29.2 s | 29.3 s | 29.4 s | 29.5 s | 29.6 s |
| 29.7 s | 29.8 s | 29.9 s | 30 s | 30.1 s | 30.2 s | 30.3 s | 30.4 s |
| 30.5 s | 30.6 s | 30.7 s | 30.8 s | 30.9 s | 31 s | 31.1 s | 31.2 s |
| 31.3 s | 31.4 s | 31.5 s | 31.6 s | 31.7 s | 31.8 s | 31.9 s | 32 s |
| 32.1 s | 32.2 s | 32.3 s | 32.4 s | 32.5 s | 32.6 s | 32.7 s | 32.8 s |
| 32.9 s | 33 s | 33.1 s | 33.2 s | 33.3 s | 33.4 s | 33.5 s | 33.6 s |
| 33.7 s | 33.8 s | 33.9 s | 34 s | 34.1 s | 34.2 s | 34.3 s | 34.4 s |
| 34.5 s | 34.6 s | 34.7 s | 34.8 s | 34.9 s | 35 s | 35.1 s | 35.2 s |
| 35.3 s | 35.4 s | 35.5 s | 35.6 s | 35.7 s | 35.8 s | 35.9 s | 36 s |
| 36.1 s | 36.2 s | 36.3 s | 36.4 s | 36.5 s | 36.6 s | 36.7 s | 36.8 s |
| 36.9 s | 37 s | 37.1 s | 37.2 s | 37.3 s | 37.4 s | 37.5 s | 37.6 s |
| 37.7 s | 37.8 s | 37.9 s | 38 s | 38.1 s | 38.2 s | 38.3 s | 38.4 s |
| 38.5 s | 38.6 s | 38.7 s | 38.8 s | 38.9 s | 39 s | 39.1 s | 39.2 s |
| 39.3 s | 39.4 s | 39.5 s | 39.6 s | 39.7 s | 39.8 s | 39.9 s | 40 s |
| 40.1 s | 40.2 s | 40.3 s | 40.4 s | 40.5 s | 40.6 s | 40.7 s | 40.8 s |
| 40.9 s | 41 s | 41.1 s | 41.2 s | 41.3 s | 41.4 s | 41.5 s | 41.6 s |
| 41.7 s | 41.8 s | 41.9 s | 42 s | 42.1 s | 42.2 s | 42.3 s | 42.4 s |
| 42.5 s | 42.6 s | 42.7 s | 42.8 s | 42.9 s | 43 s | 43.1 s | 43.2 s |
| 43.3 s | 43.4 s | 43.5 s | 43.6 s | 43.7 s | 43.8 s | 43.9 s | 44 s |
| 44.1 s | 44.2 s | 44.3 s | 44.4 s | 44.5 s | 44.6 s | 44.7 s | 44.8 s |
| 44.9 s | 45 s | 45.1 s | 45.2 s | 45.3 s | 45.4 s | 45.5 s | 45.6 s |
| 45.7 s | 45.8 s | 45.9 s | 46 s | 46.1 s | 46.2 s | 46.3 s | 46.4 s |
| 46.5 s | 46.6 s | 46.7 s | 46.8 s | 46.9 s | 47 s | 47.1 s | 47.2 s |
| 47.3 s | 47.4 s | 47.5 s | 47.6 s | 47.7 s | 47.8 s | 47.9 s | 48 s |
| 48.1 s | 48.2 s | 48.3 s | 48.4 s | 48.5 s | 48.6 s | 48.7 s | 48.8 s |
| 48.9 s | 49 s | 49.1 s | 49.2 s | 49.3 s | 49.4 s | 49.5 s | 49.6 s |
| 49.7 s | 49.8 s | 49.9 s | 50 s | ||||
| Severe prothrombin time (PT) increase | |||||||
| 50.1 s | 50.2 s | 50.3 s | 50.4 s | 50.5 s | 50.6 s | 50.7 s | 50.8 s |
| 50.9 s | 51 s | 51.1 s | 51.2 s | 51.3 s | 51.4 s | 51.5 s | 51.6 s |
| 51.7 s | 51.8 s | 51.9 s | 52 s | 52.1 s | 52.2 s | 52.3 s | 52.4 s |
| 52.5 s | 52.6 s | 52.7 s | 52.8 s | 52.9 s | 53 s | 53.1 s | 53.2 s |
| 53.3 s | 53.4 s | 53.5 s | 53.6 s | 53.7 s | 53.8 s | 53.9 s | 54 s |
| 54.1 s | 54.2 s | 54.3 s | 54.4 s | 54.5 s | 54.6 s | 54.7 s | 54.8 s |
| 54.9 s | 55 s | 55.1 s | 55.2 s | 55.3 s | 55.4 s | 55.5 s | 55.6 s |
| 55.7 s | 55.8 s | 55.9 s | 56 s | 56.1 s | 56.2 s | 56.3 s | 56.4 s |
| 56.5 s | 56.6 s | 56.7 s | 56.8 s | 56.9 s | 57 s | 57.1 s | 57.2 s |
| 57.3 s | 57.4 s | 57.5 s | 57.6 s | 57.7 s | 57.8 s | 57.9 s | 58 s |
| 58.1 s | 58.2 s | 58.3 s | 58.4 s | 58.5 s | 58.6 s | 58.7 s | 58.8 s |
| 58.9 s | 59 s | 59.1 s | 59.2 s | 59.3 s | 59.4 s | 59.5 s | 59.6 s |
| 59.7 s | 59.8 s | 59.9 s | 60 s | 60.1 s | 60.2 s | 60.3 s | 60.4 s |
| 60.5 s | 60.6 s | 60.7 s | 60.8 s | 60.9 s | 61 s | 61.1 s | 61.2 s |
| 61.3 s | 61.4 s | 61.5 s | 61.6 s | 61.7 s | 61.8 s | 61.9 s | 62 s |
| 62.1 s | 62.2 s | 62.3 s | 62.4 s | 62.5 s | 62.6 s | 62.7 s | 62.8 s |
| 62.9 s | 63 s | 63.1 s | 63.2 s | 63.3 s | 63.4 s | 63.5 s | 63.6 s |
| 63.7 s | 63.8 s | 63.9 s | 64 s | 64.1 s | 64.2 s | 64.3 s | 64.4 s |
| 64.5 s | 64.6 s | 64.7 s | 64.8 s | 64.9 s | 65 s | 65.1 s | 65.2 s |
| 65.3 s | 65.4 s | 65.5 s | 65.6 s | 65.7 s | 65.8 s | 65.9 s | 66 s |
| 66.1 s | 66.2 s | 66.3 s | 66.4 s | 66.5 s | 66.6 s | 66.7 s | 66.8 s |
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