The nurse is reviewing the lab results of a patient who takes warfarin to prevent deep vein thrombosis. Which laboratory result requires follow up by the nurse?
A.
The partial thromboplastin time is 30 seconds
B.
The International normalized ratio is 6.0
C.
Creatinine is 12
D.
The patient’s hematocrit level is 43%
The Correct Answer and Explanation is:
The correct answer is B. The International normalized ratio (INR) is 6.0.
Explanation:
Warfarin is an anticoagulant used to prevent blood clots, and its effect is monitored through the International Normalized Ratio (INR). The therapeutic range for patients on warfarin usually depends on the reason for anticoagulation but is generally between 2.0 and 3.0. For those with certain conditions, like mechanical heart valves, the target range may be slightly higher (2.5 to 3.5).
An INR of 6.0 is significantly above the therapeutic range, indicating that the blood is much thinner than intended, putting the patient at high risk for bleeding complications, such as gastrointestinal bleeding, intracranial hemorrhage, or bleeding from minor cuts or bruises. Immediate follow-up is necessary to adjust the warfarin dosage or administer reversal agents like vitamin K to reduce the risk of severe bleeding.
Why the Other Options Are Incorrect:
- A. Partial thromboplastin time (PTT) is 30 seconds:
PTT is not routinely used to monitor warfarin therapy. PTT is more commonly used for monitoring heparin therapy, another anticoagulant. The normal range for PTT is about 25-35 seconds, so 30 seconds is within the normal range and does not require follow-up in this context. - C. Creatinine is 12:
This seems to be a typographical error, as creatinine levels above 12 mg/dL would indicate severe kidney failure and would require urgent attention. However, in most clinical labs, creatinine levels above 2 mg/dL are concerning. If this was intended to indicate something else, the value provided needs clarification, as creatinine primarily reflects kidney function, not warfarin therapy. - D. Hematocrit level is 43%:
A hematocrit of 43% falls within the normal range for adults (normal range: 38-48% for women and 40-52% for men). This result does not require immediate follow-up, as it does not indicate any abnormalities related to warfarin or bleeding.
Conclusion:
An INR of 6.0 is dangerously high, and the patient is at increased risk for bleeding. Immediate follow-up is necessary to assess for bleeding symptoms, adjust the warfarin dose, and possibly reverse its effects. Monitoring INR is critical in patients taking warfarin to maintain a balance between preventing clots and avoiding excessive bleeding.