diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6132178e..dc586ac9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,7 @@
 **Version 4.2**
 
  - Fixed a bug in the dictionary validation that would not flag as invalid a dictionary with a missing URI attribute.
+ - Added support in NaaccrXmlUtils for new lineToPatient and patientToLine methods.
 
 **Version 4.1**
 
diff --git a/README.md b/README.md
index 397c7373..6a5f09c0 100644
--- a/README.md
+++ b/README.md
@@ -74,14 +74,18 @@ A few higher-level utility methods have been defined in the [NaaccrXmlUtils](htt
 *Translation methods*
 * void ***flatToXml*** (File flatFile, File xmlFile, ...)
 * void ***xmlToFlat*** (File xmlFile, File flatFile, ...)
+* Patient ***lineToPatient*** (String line, NaaccrContext context)
+* String ***patientToLine*** (Patient patient, NaaccrContext context)
 
 There are other utility methods, but those are the main ones.
 
-All those methods accept the following optional parameters (optional in the sense that null can be passed to the method):
+All the file-related methods accept the following optional parameters (optional in the sense that null can be passed to the method):
 * [NaaccrXmlOptions](https://github.com/imsweb/naaccr-xml/blob/master/src/main/java/com/imsweb/naaccrxml/NaaccrXmlOptions.java) - options for customizing the read/write and errors reporting operations
 * [NaaccrDictionary](https://github.com/imsweb/naaccr-xml/blob/master/src/main/java/com/imsweb/naaccrxml/entity/dictionary/NaaccrDictionary.java) - one or several user-defined dictionary (if none is provided, the default user-defined dictionary will be used)
 * [NaaccrObserver](https://github.com/imsweb/naaccr-xml/blob/master/src/main/java/com/imsweb/naaccrxml/NaaccrObserver.java) - an observer allowing to report progress as the files are being processed.
 
+The methods translating a single line or single patient takes a context as parameter; it is very important to initialize that context outside a loop if the methods are called in a loop.
+
 ### Using the Graphical User Interface (Standalone)
 
 The library contains an standalone GUI that wraps some of the utility methods and provides a more user-friendly environment for processing files.
diff --git a/src/main/java/com/imsweb/naaccrxml/NaaccrXmlUtils.java b/src/main/java/com/imsweb/naaccrxml/NaaccrXmlUtils.java
index b369de0b..537a8b66 100644
--- a/src/main/java/com/imsweb/naaccrxml/NaaccrXmlUtils.java
+++ b/src/main/java/com/imsweb/naaccrxml/NaaccrXmlUtils.java
@@ -253,7 +253,23 @@ public static void writeFlatFile(NaaccrData data, File flatFile, NaaccrOptions o
     /**
      * Translates a single line representing a flat file line into a patient object.
      * <br/><br/>
-     * TODO explain the context
+     * Unlike the methods dealing with files, this method takes a context as a parameter. The reason for that difference is that this method uses a stream to convert
+     * the line, and so the stream needs to be re-created every time the method is invoked on a given line. This is very inefficient and would be too slow if this
+     * method was used in a loop (which is the common use-case). Having a shared context that is created once outside the loop avoids that inefficiency.
+     * <br/><br/>
+     * It is very important to not re-create the context when this method is called in a loop:
+     * <br><br/>
+     * This is NOT correct:
+     * <code>
+     *     for (String line : lines)
+     *         NaaccrXmlUtils.lineToPatient(line, new NaaccrContext(NaaccrFormat.NAACCR_FORMAT_16_ABSTRACT));
+     * </code>
+     * This is correct:
+     * <code>
+     *     NaaccrContext context = new NaaccrContext(NaaccrFormat.NAACCR_FORMAT_16_ABSTRACT);
+     *     for (String line : lines)
+     *         NaaccrXmlUtils.lineToPatient(line, context);
+     * </code>
      * @param line the line to translate, required
      * @param context the context to use for the translation, required
      * @return the corresponding patient, never null
@@ -265,7 +281,18 @@ public static Patient lineToPatient(String line, NaaccrContext context) throws N
         if (context == null)
             throw new NaaccrIOException("Context is required");
 
-        // TODO inject format if not provided on the line
+        NaaccrFormat format = NaaccrFormat.getInstance(context.getFormat());
+        if (line.length() != format.getLineLength())
+            throw new NaaccrIOException("Expected line length to be " + format.getLineLength() + " but was " + line.length());
+
+        boolean updateType = !format.getRecordType().equals(line.substring(0, 1).trim());
+        boolean updateVersion = !format.getNaaccrVersion().equals(line.substring(16, 19).trim());
+        if (updateType || updateVersion) {
+            StringBuilder buf = new StringBuilder(line);
+            buf.replace(0, 1, format.getRecordType());
+            buf.replace(16, 19, format.getNaaccrVersion());
+            line = buf.toString();
+        }
 
         try (PatientFlatReader reader = new PatientFlatReader(new StringReader(line), context.getOptions(), context.getUserDictionaries(), context.getStreamConfiguration())) {
             return reader.readPatient();
@@ -275,7 +302,23 @@ public static Patient lineToPatient(String line, NaaccrContext context) throws N
     /**
      * Translates a single patient into a line representing a flat file line.
      * <br/><br/>
-     * TODO explain the context
+     * Unlike the methods dealing with files, this method takes a context as a parameter. The reason for that difference is that this method uses a stream to convert
+     * the patient, and so the stream needs to be re-created every time the method is invoked on a given patient. This is very inefficient and would be too slow if this
+     * method was used in a loop (which is the common use-case). Having a shared context that is created once outside the loop avoids that inefficiency.
+     * <br/><br/>
+     * It is very important to not re-create the context when this method is called in a loop:
+     * <br><br/>
+     * This is NOT correct:
+     * <code>
+     *     for (Patient patient : patients)
+     *         NaaccrXmlUtils.patientToLine(patient, new NaaccrContext(NaaccrFormat.NAACCR_FORMAT_16_ABSTRACT));
+     * </code>
+     * This is correct:
+     * <code>
+     *     NaaccrContext context = new NaaccrContext(NaaccrFormat.NAACCR_FORMAT_16_ABSTRACT);
+     *     for (Patient patient : patients)
+     *         NaaccrXmlUtils.patientToLine(patient, context);
+     * </code>
      * @param patient the patient to translate, required
      * @param context the context to use for the translation, required
      * @return the corresponding line, never null
diff --git a/src/test/java/com/imsweb/naaccrxml/NaaccrXmlUtilsTest.java b/src/test/java/com/imsweb/naaccrxml/NaaccrXmlUtilsTest.java
index 050193df..d2f26179 100644
--- a/src/test/java/com/imsweb/naaccrxml/NaaccrXmlUtilsTest.java
+++ b/src/test/java/com/imsweb/naaccrxml/NaaccrXmlUtilsTest.java
@@ -158,6 +158,56 @@ public void testWriteXmlFile() throws IOException {
         }
     }
 
+    @Test
+    public void testLineToPatient() throws IOException {
+        StringBuilder line = TestingUtils.createEmptyRecord("160", "A", "00000001");
+
+        NaaccrContext context = new NaaccrContext(NaaccrFormat.NAACCR_FORMAT_16_ABSTRACT);
+        Patient patient = NaaccrXmlUtils.lineToPatient(line.toString(), context);
+        Assert.assertEquals("00000001", patient.getItemValue("patientIdNumber"));
+
+        List<NaaccrDictionary> dictionaries = Collections.singletonList(TestingUtils.createUserDictionary());
+        line.replace(2339, 2341, "00");
+        context = new NaaccrContext(NaaccrFormat.NAACCR_FORMAT_16_ABSTRACT, dictionaries);
+        patient = NaaccrXmlUtils.lineToPatient(line.toString(), context);
+        Assert.assertEquals("00", patient.getTumors().get(0).getItemValue("myVariable"));
+
+        NaaccrOptions options = NaaccrOptions.getDefault();
+        options.setItemsToExclude(Collections.singletonList("patientIdNumber"));
+        context = new NaaccrContext(NaaccrFormat.NAACCR_FORMAT_16_ABSTRACT, dictionaries, options);
+        patient = NaaccrXmlUtils.lineToPatient(line.toString(), context);
+        Assert.assertNull(patient.getItemValue("patientIdNumber"));
+
+        line.replace(0, 20, "                    ");
+        context = new NaaccrContext(NaaccrFormat.NAACCR_FORMAT_16_ABSTRACT);
+        patient = NaaccrXmlUtils.lineToPatient(line.toString(), context);
+        Assert.assertEquals("00000001", patient.getItemValue("patientIdNumber"));
+    }
+
+    @Test
+    public void testPatientToLine() throws IOException {
+        Patient patient = new Patient();
+        patient.addItem(new Item("patientIdNumber", "00000001"));
+
+        NaaccrContext context = new NaaccrContext(NaaccrFormat.NAACCR_FORMAT_16_ABSTRACT);
+        String line = NaaccrXmlUtils.patientToLine(patient, context);
+        Assert.assertEquals("00000001", line.substring(41, 49));
+
+        List<NaaccrDictionary> dictionaries = Collections.singletonList(TestingUtils.createUserDictionary());
+        Tumor tumor = new Tumor();
+        patient.addTumor(tumor);
+        tumor.addItem(new Item("myVariable", "00"));
+        context = new NaaccrContext(NaaccrFormat.NAACCR_FORMAT_16_ABSTRACT, dictionaries);
+        line = NaaccrXmlUtils.patientToLine(patient, context);
+        Assert.assertEquals("00", line.substring(2339, 2341));
+
+        NaaccrOptions options = NaaccrOptions.getDefault();
+        options.setItemsToExclude(Collections.singletonList("patientIdNumber"));
+        context = new NaaccrContext(NaaccrFormat.NAACCR_FORMAT_16_ABSTRACT, dictionaries, options);
+        line = NaaccrXmlUtils.patientToLine(patient, context);
+        Assert.assertEquals("        ", line.substring(41, 49));
+    }
+
     @Test
     public void testGetFormatFromFlatFile() throws IOException {