Objective 3. Keyword Search Steps: Term Variants, Join Terms

Now that you’ve gathered term lists, it’s time to think about the variants of the gathered terms that might exist.

Does your list suggest variants?

You’ve developed the following terms lists below.  Does a simple review of the term lists suggest any other term variants?

paroxysmal nocturnal hemoglobinuria

• paroxysmal nocturnal hemoglobinuria
• paroxysmal hemoglobinuria
• paroxysmal cold hemoglobinuria
• Cold Paroxysmal Hemoglobinuria
• Paroxysmal Nocturnal Hemoglobinuria
• Marchiafava-Micheli Syndrome
• Marchiafava Micheli Syndrome
• Nocturnal Paroxysmal Hemoglobinuria
• PNH
• paroxysmal haemoglobinuria
• intermittent haematuria
• paroxysmal haematuria
• paroxysmal haematinuria

eculizumab

• eculizumab
• Alexion
• Elizaria
• Soliris
• 5G1.1
• H5G1.1VHC+H5G1.1VLC
• H5G1.1
• H5G1-1
• H5G11
• 219685-50-4
• eculizumabum
• Acveris

Thrombosis

• Blood Clot
• Blood Clots
• budd chiari
• embolism
• embolus
• postthrombotic
• thromboembolism
• thromboinflammation
• thromboses
• thrombosis
• Thrombus

The presence of the “intermittent haematuria” term brings to mind the possibility of “intermittent haemoglobinuria” and “intermittent haematinuria” and the American spellings of these words. Whenever you encounter multiple similar multi-word phrases, consider simplifying your search by splitting the phrases into a multi-subconcept search term. The “paroxysmal nocturnal hemoglobinuria” search can be simplified by splitting the paroxysmal subconcept and the hemoglobinuria/hemolysis subconcept as shown below:

((intermittent OR paroxysmal ) AND ( haemoglobinuria OR hemoglobinuria OR haematuria OR hematuria OR haematinuria OR hematinuria))
PNH
Marchiafava-Micheli Syndrome
Marchiafava Micheli Syndrome

Tips for including relevant variants

To be sure you’ve found all needed variants, ask yourself the bulleted questions listed below:

While considering the bulleted questions, remember a single word trunk followed by  the asterisk wildcard can retrieve multiple different word forms (e.g. haemoly* can retrieve haemolysis, haemolyses, haemolytic, etc.).  Also a PubMed search for a hyphenated term will also find that term if it contains a space rather than a hyphen.

• Have you removed any non-essential words from multi-word phrases?
  • The words “disease” and “syndrome” can usually be removed from eponymous disease names.  Use a title/abstract tag [tiab] after the eponym to keep the eponym from finding author’s names.
• Are both singular and plural forms of nouns present or represented by truncated terms?
• If your term list includes any verbs, are all forms of the verb included (ex. erode,erodes,eroded,eroding) or represented by truncated terms
• If your term list includes verbs, have you included any noun forms of those verbs (ex. erosion, erosions) or represented these with truncated terms
• If your term list includes nouns, have any adjective forms of those nouns been included (ex. neuropathic for neuropathy) or represented by truncated terms
• If your term list includes adjectives, have you included any adverb forms of those adjectives (ex. quick, quickly) or represented by truncated terms
• Have you included British as well as American spellings?
• Have you included any commonly used abbreviations (ex. NIDDM for non-insulin-dependent diabetes mellitus)
• Have you included relevant opposites? (e.g. If your search includes a safety concept, in addition to the safety words, you need to include danger/harzard/etc. words.)

Add additional terms to your list until you can answer yes or not applicable to each of the above questions.

Revised term lists

The shortest versions of the revised term lists would look something like the following:

• Eculizumab*
• 219685-50-4
• h5G1.1*
• h5g11
• h5G1-1
• 5G1.1
• Soliris
• Elizaria
• Alexion
• Acveris

• ((intermittent OR paroxysmal ) AND ( haemoglobinur* OR hemoglobinur* OR haematur* OR hematur* OR haematinur* OR hematinur*))
• PNH
• Marchiafava-Micheli [tiab]

• Clot
• Clots (clot* might retrieve cloth, clothing, etc.)
• budd-chiari[tiab]
• embol*
• postthromb*
• thromb*

A couple points to keep in mind for future searches:

• Words that end in -sis like hemolysis should usually be truncated before the -sis. This allows retrieval of the plural -ses form (e.g. hemolyses) and the adjective -tic form (e.g. hemolytic).
• Words that end in -ia like hematinuria should usually be truncated after the -i. This allows retrieval of the adjective -ic form (e.g. hematinuric).

Step 3 – 6.  Create search strategies for individual concepts

Step 3.  Enclose any multi-word terms (terms containing spaces) with quotation marks

Step 4. Truncate any terms with multiple useful endings using asterisks and remove any words that are no longer needed because of the truncation of other terms.

Exciting News (if you are a search geek like me):  The new PubMed can handle truncated phrases!  You can only truncate the last word in the phrase, (e.g. “dog bite*”)

Step 5.  Join the alternate terms for a single concept using OR.

Step 6.  Place parentheses around the OR’d together term list.

Did you come up with search statements/strategies similar to those shown below?

(Eculizumab* OR 219685-50-4 OR h5G1.1* OR h5g11 OR h5G1-1 OR 5G1.1 OR Soliris OR Elizaria OR Alexion OR Acveris)

(((intermittent OR paroxysmal ) AND ( haemoglobinur* OR hemoglobinur* OR haematur* OR hematur* OR haematinur* OR hematinur*)) OR PNH OR Marchiafava-Micheli [tiab])

(Clot OR Clots  OR budd-chiari[tiab] OR embol* OR postthromb* OR thromb*)

If you’ve found problems with your search statements/strategies, correct them. Feel free to ask the for help or clarification.

Step 7.  Join the Disparate Concepts

Now it’s time to join the “paroxysmal nocturnal hemoglobinuria” keyword search statement to the “eculizumab” keyword search statement. What Boolean Operator (AND, OR, or NOT) should be used for this operation?

Did you come up with a search statement/strategy similar to the strategy below?

(Eculizumab* OR 219685-50-4 OR h5G1.1* OR h5g11 OR h5G1-1 OR 5G1.1 OR Soliris OR Elizaria OR Alexion OR Acveris) AND (((intermittent OR paroxysmal ) AND ( haemoglobinur* OR hemoglobinur* OR haematur* OR hematur* OR haematinur* OR hematinur*)) OR PNH OR Marchiafava-Micheli [tiab]) AND (Clot OR Clots  OR budd-chiari[tiab] OR embol* OR postthromb* OR thromb*)