```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>(t) Digesti-ALT (SGDigestiALT (SG@16:27:42</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>2</hlevel>
            <item_name>Digestive system</item_name>
            <item_key>\\i2b2_DIAG\i2b2\Diagnoses\Digestive system (520-579)\</item_key>
            <item_icon>FA</item_icon>
            <tooltip>Diagnoses \ Digestive system</tooltip>
            <class>ENC</class>
            <item_is_synonym>false</item_is_synonym>
        </item>
    </panel>
    <panel>
        <panel_number>2</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>5</hlevel>
            <item_name>ALT (SGPT) (LOINC:1742-6)</item_name>
            <item_key>\\i2b2_LABS\i2b2\Labtests\LAB\(LLB16) Chemistry\(LLB25) Liver Function Tests\SGPT\LOINC:1742-6\</item_key>
            <item_icon>LA</item_icon>
            <tooltip>Labtests \ Chemistry \ Liver Function Tests \ ALT (SGPT) (Group:SGPT) \ ALT (SGPT) (LOINC:1742-6)</tooltip>
            <class>ENC</class>
            <item_is_synonym>false</item_is_synonym>
        </item>
    </panel>
    <subquery_constraint>
        <first_query>
            <query_id>Observation B</query_id>
            <join_column>STARTDATE</join_column>
            <aggregate_operator>FIRST</aggregate_operator>
        </first_query>
        <operator>LESS</operator>
        <second_query>
            <query_id>Observation D</query_id>
            <join_column>STARTDATE</join_column>
            <aggregate_operator>FIRST</aggregate_operator>
        </second_query>
    </subquery_constraint>
    <subquery>
        <query_id>Observation B</query_id>
        <query_type>EVENT</query_type>
        <query_name>Observation B</query_name>
        <query_timing>SAMEINSTANCENUM</query_timing>
        <specificity_scale>0</specificity_scale>
        <panel>
            <panel_number>0</panel_number>
            <panel_timing>SAMEINSTANCENUM</panel_timing>
            <panel_accuracy_scale>100</panel_accuracy_scale>
            <invert>0</invert>
            <total_item_occurrences>1</total_item_occurrences>
            <item>
                <hlevel>2</hlevel>
                <item_name>Digestive system</item_name>
                <item_key>\\i2b2_DIAG\i2b2\Diagnoses\Digestive system (520-579)\</item_key>
                <item_icon>FA</item_icon>
                <tooltip>Diagnoses \ Digestive system</tooltip>
                <class>ENC</class>
                <item_is_synonym>false</item_is_synonym>
            </item>
        </panel>
    </subquery>
    <subquery>
        <query_id>Observation D</query_id>
        <query_type>EVENT</query_type>
        <query_name>Observation D</query_name>
        <query_timing>SAMEINSTANCENUM</query_timing>
        <specificity_scale>0</specificity_scale>
        <panel>
            <panel_number>0</panel_number>
            <panel_timing>SAMEINSTANCENUM</panel_timing>
            <panel_accuracy_scale>100</panel_accuracy_scale>
            <invert>0</invert>
            <total_item_occurrences>1</total_item_occurrences>
            <item>
                <hlevel>5</hlevel>
                <item_name>ALT (SGPT) (LOINC:1742-6)</item_name>
                <item_key>\\i2b2_LABS\i2b2\Labtests\LAB\(LLB16) Chemistry\(LLB25) Liver Function Tests\SGPT\LOINC:1742-6\</item_key>
                <item_icon>LA</item_icon>
                <tooltip>Labtests \ Chemistry \ Liver Function Tests \ ALT (SGPT) (Group:SGPT) \ ALT (SGPT) (LOINC:1742-6)</tooltip>
                <class>ENC</class>
                <item_is_synonym>false</item_is_synonym>
            </item>
        </panel>
    </subquery>
</ns4:query_definition>

```

I want to find all instances where a patient has a diagnosis related to the digestive system (ICD codes 520-579) and also has a lab test result for ALT (SGPT) (LOINC:1742-6) with a value less than the first observation. The query is looking for occurrences where the ALT (SGPT) test result happened after the digestive system diagnosis, and the test result is lower than the first observation recorded for that patient.