Wells score (pulmonary embolism)
{{Short description|Estimates probability of pulmonary embolism}}
{{primary sources|date=November 2022}}
The Wells score is a clinical prediction rule used to classify patients suspected of having pulmonary embolism (PE) into risk groups by quantifying the pre-test probability. It is different than Wells score for DVT (deep vein thrombosis). It was originally described by Wells et al. in 1998,{{Cite journal |last1=Wells |first1=Philip S. |last2=Ginsberg |first2=Jeffrey S. |last3=Anderson |first3=David R. |last4=Kearon |first4=Clive |last5=Gent |first5=Michael |last6=Turpie |first6=Alexander G. |last7=Bormanis |first7=Janis |last8=Weitz |first8=Jeffrey |last9=Chamberlain |first9=Michael |last10=Bowie |first10=Dennis |last11=Barnes |first11=David |last12=Hirsh |first12=Jack |date=1998-12-15 |title=Use of a Clinical Model for Safe Management of Patients with Suspected Pulmonary Embolism |url=https://www.acpjournals.org/doi/10.7326/0003-4819-129-12-199812150-00002 |journal=Annals of Internal Medicine |volume=129 |issue=12 |pages=997–1005 |doi=10.7326/0003-4819-129-12-199812150-00002 |pmid=9867786 |s2cid=41389736 |issn=0003-4819|url-access=subscription }} using their experience from creating Wells score for DVT in 1995.{{Cite journal |last1=Wells |first1=P. S. |last2=Hirsh |first2=J. |last3=Anderson |first3=D. R. |last4=Lensing |first4=A. W. |last5=Foster |first5=G. |last6=Kearon |first6=C. |last7=Weitz |first7=J. |last8=D'Ovidio |first8=R. |last9=Cogo |first9=A. |last10=Prandoni |first10=P. |date=1995-05-27 |title=Accuracy of clinical assessment of deep-vein thrombosis |url=https://pubmed.ncbi.nlm.nih.gov/7752753/ |journal=Lancet |volume=345 |issue=8961 |pages=1326–1330 |doi=10.1016/s0140-6736(95)92535-x |issn=0140-6736 |pmid=7752753|s2cid=23107192 }} Today, there are multiple (revised or simplified) versions of the rule, which may lead to ambiguity.{{Cite journal |last1=Wells |first1=P. S. |last2=Anderson |first2=D. R. |last3=Rodger |first3=M. |last4=Ginsberg |first4=J. S. |last5=Kearon |first5=C. |last6=Gent |first6=M. |last7=Turpie |first7=A. G. |last8=Bormanis |first8=J. |last9=Weitz |first9=J. |last10=Chamberlain |first10=M. |last11=Bowie |first11=D. |last12=Barnes |first12=D. |last13=Hirsh |first13=J. |date=March 2000 |title=Derivation of a simple clinical model to categorize patients probability of pulmonary embolism: increasing the models utility with the SimpliRED D-dimer |url=https://pubmed.ncbi.nlm.nih.gov/10744147/ |journal=Thrombosis and Haemostasis |volume=83 |issue=3 |pages=416–420 |doi=10.1055/s-0037-1613830 |issn=0340-6245 |pmid=10744147|s2cid=10013631 }}{{Cite journal |last1=Wells |first1=Philip S. |last2=Anderson |first2=David R. |last3=Rodger |first3=Marc |last4=Stiell |first4=Ian |last5=Dreyer |first5=Jonathan F. |last6=Barnes |first6=David |last7=Forgie |first7=Melissa |last8=Kovacs |first8=George |last9=Ward |first9=John |last10=Kovacs |first10=Michael J. |date=2001-07-17 |title=Excluding Pulmonary Embolism at the Bedside without Diagnostic Imaging: Management of Patients with Suspected Pulmonary Embolism Presenting to the Emergency Department by Using a Simple Clinical Model and d-dimer |url=https://www.acpjournals.org/doi/10.7326/0003-4819-135-2-200107170-00010 |journal=Annals of Internal Medicine |volume=135 |issue=2 |pages=98–107 |doi=10.7326/0003-4819-135-2-200107170-00010 |pmid=11453709 |s2cid=2708155 |issn=0003-4819|url-access=subscription }}
The purpose of the rule is to select the best method of investigation (e.g. D-dimer testing, CT angiography) for ruling in or ruling out the diagnosis of PE, and to improve the interpretation and accuracy of subsequent testing, based on a Bayesian framework for the probability of the diagnosis.
The rule is more objective than clinician gestalt, but still includes subjective opinion (unlike e.g. Geneva score).
Original algorithm<ref name=":0" />
Originally it was developed in 1998 to improve the low specificity of V/Q scan results (which then had a more important role in the workup of PE than now).
It categorized patients into 3 categories: low / moderate / high probability. It was formulated in the form of an algorithm, not a score.
Subsequent testing choices were V/Q scanning, pulmonary angiography, and serial compression ultrasound.
Revised score <ref name=":1" /><ref name=":2" />
{{Expand section|small=|find=pulmonary embolism|date=November 2022}}
The emergence of rapid D-dimer assays in 1995{{Cite journal |last=Ginsberg |first=J. S. |last2=Wells |first2=P. S. |last3=Brill-Edwards |first3=P. |last4=Donovan |first4=D. |last5=Panju |first5=A. |last6=van Beek |first6=E. J. |last7=Patel |first7=A. |date=Jan 1995 |title=Application of a novel and rapid whole blood assay for D-dimer in patients with clinically suspected pulmonary embolism |url=https://pubmed.ncbi.nlm.nih.gov/7740493 |journal=Thrombosis and Haemostasis |volume=73 |issue=1 |pages=35–38 |issn=0340-6245 |pmid=7740493}} prompted revision of the rule. The D-dimer assay and the revised Wells score can be combined to identify a population with a pre-test probability of PE of less than 2%.{{Cite journal |last=Wells |first=P. S. |last2=Anderson |first2=D. R. |last3=Rodger |first3=M. |last4=Ginsberg |first4=J. S. |last5=Kearon |first5=C. |last6=Gent |first6=M. |last7=Turpie |first7=A. G. |last8=Bormanis |first8=J. |last9=Weitz |first9=J. |last10=Chamberlain |first10=M. |last11=Bowie |first11=D. |last12=Barnes |first12=D. |last13=Hirsh |first13=J. |date=March 2000 |title=Derivation of a simple clinical model to categorize patients probability of pulmonary embolism: increasing the models utility with the SimpliRED D-dimer |url=https://pubmed.ncbi.nlm.nih.gov/10744147 |journal=Thrombosis and Haemostasis |volume=83 |issue=3 |pages=416–420 |issn=0340-6245 |pmid=10744147}}
This version was published as a score, and according to the final score, patients could be categorized in either 3 groups (low / intermediate / high risk) or 2 groups (PE unlikely/ PE likely).
Subsequent testing choices included D-dimer testing for low risk cases to further understand the pre-test probability; and V/Q scanning, pulmonary angiography, and compression ultrasonography for intermediate / high risk patients and low-risk patients with positive D-dimer results.
| class="wikitable"
!Variable !Points |
| Clinical signs and symptoms of DVT
|3 |
| An alternate diagnosis is less likely than PE
|3 |
| Heart rate >100
|1.5 |
| Immobilization or surgery in the previous 4 weeks
|1.5 |
| Previous DVT / PE
|1.5 |
| Hemoptysis
|1 |
| Malignancy (treatment currently, in the previous 6 months, or palliative)
|1 |
Risk of PE using 3 categories (data from the derivation group)
| class="wikitable"
!Risk group !Points required !Risk of PE |
| Low risk
|0-1 |3.6% |
| Moderate risk
|2-6 |20.5% |
| High risk
|>6 |66.7% |
Risk of PE using 2 categories (data from the derivation group)
| class="wikitable"
!Risk group !Points required !Risk of PE |
| Low
|0-4 |5.1% |
| High
|>4 |39.1% |