```xml
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ns4:query_definition xmlns:ns2="http://www.i2b2.org/xsd/cell/crc/psm/1.1/" xmlns:ns4="http://www.i2b2.org/xsd/cell/crc/psm/querydefinition/1.1/" xmlns:ns3="http://www.i2b2.org/xsd/cell/crc/psm/analysisdefinition/1.1/">
    <query_name>Singulair 5mg tablet chewable Merck &amp; Co. Inc@19:49:52</query_name>
    <query_timing>ANY</query_timing>
    <specificity_scale>0</specificity_scale>
    <panel>
        <panel_number>1</panel_number>
        <panel_timing>ANY</panel_timing>
        <panel_accuracy_scale>100</panel_accuracy_scale>
        <invert>0</invert>
        <total_item_occurrences>1</total_item_occurrences>
        <item>
            <hlevel>1</hlevel>
            <item_name>Singulair 5mg tablet chewable Merck &amp; Co. Inc</item_name>
            <item_key>\\i2b2_MEDS\i2b2\Medications\MUL\(LME219) respiratory agents\(LME229) leukotriene modifiers\montelukast\00006027531\</item_key>
            <item_icon>FA</item_icon>
            <tooltip>medications \ respiratory agents \ leukotriene modifiers \ montelukast \ singulair 5mg tablet chewable merck &amp; co. inc</tooltip>
            <class>ENC</class>
            <constrain_by_modifier>
                <modifier_name>Patient Instructions</modifier_name>
                <modifier_key>\\i2b2_MEDS\Medication\Instructions\</modifier_key>
                <applied_path>\i2b2\Medications\%</applied_path>
                <constrain_by_value>
                    <value_operator>CONTAINS</value_operator>
                    <value_constraint>test</value_constraint>
                    <value_type>LARGETEXT</value_type>
                </constrain_by_value>
            </constrain_by_modifier>
            <item_is_synonym>false</item_is_synonym>
        </item>
    </panel>
</ns4:query_definition>

```

I want to find all instances of the medication "Singulair 5mg tablet chewable" manufactured by Merck & Co. Inc. within the i2b2 database, with no specific time frame, and the highest level of accuracy. The query will be focused on the medication name and the manufacturer, and will include any records that contain the term "test" within the "Patient Instructions" field.