diff --git a/__tests__/hl7.build.test.ts b/__tests__/hl7.build.test.ts
index 523d0c6..fabf989 100644
--- a/__tests__/hl7.build.test.ts
+++ b/__tests__/hl7.build.test.ts
@@ -7,8 +7,7 @@ describe('node hl7 client - builder tests', () => {
 
     test("error - Message Object - nothing passed", async () => {
       try {
-        // @ts-expect-error Should error out..
-        const message = new Message()
+        new Message()
       } catch (err) {
         expect(err).toEqual(new Error('mshHeader must be set if no HL7 message is being passed.'))
       }
@@ -16,8 +15,7 @@ describe('node hl7 client - builder tests', () => {
 
     test("error - Message Object - text empty ", async () => {
       try {
-        // @ts-expect-error Message is not used. That's fine.
-        const message = new Message({ text: ""})
+        new Message({ text: ""})
       } catch (err) {
         expect(err).toEqual(new Error('mshHeader must be set if no HL7 message is being passed.'))
       }
@@ -25,8 +23,7 @@ describe('node hl7 client - builder tests', () => {
 
     test("error - Message Object - text must start with MSH ", async () => {
       try {
-        // @ts-expect-error Message is not used. That's fine.
-        const message = new Message({ text: "PV1|||||||^Jones\rMSH|^~\\&\r"})
+        new Message({ text: "PV1|||||||^Jones\rMSH|^~\\&\r"})
       } catch (err) {
         expect(err).toEqual(new Error('text must begin with the MSH segment.'))
       }
@@ -34,8 +31,7 @@ describe('node hl7 client - builder tests', () => {
 
     test("error - Message Object - msh 9.1 is empty ", async () => {
       try {
-        // @ts-expect-error Message is not used. That's fine.
-        const message = new Message({
+        new Message({
           mshHeader: {
             msh_9: {
               // @ts-expect-error 9.1 should be not empty
@@ -50,8 +46,7 @@ describe('node hl7 client - builder tests', () => {
 
     test("error - Message Object - msh 9.2 is empty ", async () => {
       try {
-        // @ts-expect-error Message is not used. That's fine.
-        const message = new Message({
+        new Message({
           mshHeader: {
             msh_9: {
               // @ts-expect-error 9.2 should be not empty
@@ -66,8 +61,7 @@ describe('node hl7 client - builder tests', () => {
 
     test("error - Message Object - msh 9.3 is empty ", async () => {
       try {
-        // @ts-expect-error Message is not used. That's fine.
-        const message = new Message({
+        new Message({
           mshHeader: {
             msh_9: {
               // @ts-expect-error 9.3 should be not empty
@@ -82,8 +76,7 @@ describe('node hl7 client - builder tests', () => {
 
     test("error - Message Object - msh 9.1 is not 3 character long ", async () => {
       try {
-        // @ts-expect-error Message is not used. That's fine.
-        const message = new Message({
+        new Message({
           mshHeader: {
             msh_9: {
               // @ts-expect-error 9.1 should be 3 characters
@@ -100,8 +93,7 @@ describe('node hl7 client - builder tests', () => {
 
     test("error - Message Object - msh 9.2 is not 3 character long ", async () => {
       try {
-        // @ts-expect-error Message is not used. That's fine.
-        const message = new Message({
+        new Message({
           mshHeader: {
             msh_9: {
               msh_9_1: "ADT",
@@ -118,8 +110,7 @@ describe('node hl7 client - builder tests', () => {
 
     test("error - Message Object - msh 10 is more than 199 characters ", async () => {
       try {
-        // @ts-expect-error Message is not used. That's fine.
-        const message = new Message({
+        new Message({
           mshHeader: {
             msh_9: {
               msh_9_1: "ADT",
@@ -135,8 +126,7 @@ describe('node hl7 client - builder tests', () => {
 
     test("error - Message Object - msh 10 can not be blank", async () => {
       try {
-        // @ts-expect-error Message is not used. That's fine.
-        const message = new Message({
+        new Message({
           mshHeader: {
             msh_9: {
               msh_9_1: "ADT",
@@ -169,7 +159,6 @@ describe('node hl7 client - builder tests', () => {
       })
       expect(message.toString()).toContain("MSH|^~\\&")
       expect(message.toString()).toContain(`|ADT^A01^ADT_A01|${randomControlID}||2.7`)
-
     })
 
   })
diff --git a/src/message.ts b/src/message.ts
index 0e1cfef..aaa8109 100644
--- a/src/message.ts
+++ b/src/message.ts
@@ -62,10 +62,8 @@ export class Message extends NodeBase {
       this._matchEscape = Message._makeMatchEscape(this._delimiters)
     }
 
-    if (typeof this._opt.mshHeader !== 'undefined' && this._opt.text === '') {
+    if (typeof this._opt.mshHeader !== 'undefined') {
       if (this._opt.specification.checkMSH(this._opt.mshHeader) === true) {
-        this.set('MSH.1', `${this._opt.separatorField}`)
-        this.set('MSH.2', `${this._opt.separatorComponent}${this._opt.separatorRepetition}${this._opt.separatorEscape}${this._opt.separatorSubComponent}`)
         this.set('MSH.7', Util.createDate(new Date()))
         this.set('MSH.9.1', this._opt.mshHeader.msh_9.msh_9_1.toString())
         this.set('MSH.9.2', this._opt.mshHeader.msh_9.msh_9_2.toString())
diff --git a/src/nodeBase.ts b/src/nodeBase.ts
index ec204d3..60d9975 100644
--- a/src/nodeBase.ts
+++ b/src/nodeBase.ts
@@ -9,7 +9,7 @@ import { Message } from './message.js'
 export class NodeBase implements Node {
   protected parent: NodeBase | null
 
-  private _name: string
+  _name: string
   private _text: string
   private readonly _delimiter: Delimiters | undefined
   private _delimiterText: string
@@ -60,7 +60,8 @@ export class NodeBase implements Node {
           this.set(`${path}.${i + 1}`, value[i])
         }
       } else {
-        this.write(this.preparePath(path), this.prepareValue(value))
+        const _path = this.preparePath(path)
+        this.write(_path, this.prepareValue(value))
       }
 
       return this
@@ -84,7 +85,9 @@ export class NodeBase implements Node {
   }
 
   get name (): string {
-    if (this._name !== undefined) return this._name
+    if (this._name !== undefined) {
+      return this._name
+    }
     this._name = this.path.join('.')
     return this._name
   }
@@ -310,7 +313,7 @@ export class NodeBase implements Node {
   protected setDirty (): void {
     if (!this._dirty) {
       this._dirty = true
-      if (this.parent !== null) {
+      if (typeof this.parent !== 'undefined' && this.parent !== null) {
         this.parent.setDirty()
       }
     }
diff --git a/src/normalize.ts b/src/normalize.ts
index 8c6f7f3..ec9b79b 100644
--- a/src/normalize.ts
+++ b/src/normalize.ts
@@ -197,6 +197,10 @@ export function normalizedClientBuilderOptions (raw?: ClientBuilderOptions): Cli
     throw new Error('newLine must be \r or \n')
   }
 
+  if (props.text === '') {
+    props.text = `MSH${props.separatorField}${props.separatorComponent}${props.separatorRepetition}${props.separatorEscape}${props.separatorSubComponent}`
+  }
+
   return props
 }
 
diff --git a/src/segment.ts b/src/segment.ts
index 8b5cb7d..c3b858d 100644
--- a/src/segment.ts
+++ b/src/segment.ts
@@ -26,6 +26,7 @@ export class Segment extends NodeBase {
       throw new Error('Segment must have a name.')
     }
     this._segmentName = text.slice(0, 3)
+    this._name = this._segmentName
   }
 
   /**
@@ -51,10 +52,18 @@ export class Segment extends NodeBase {
      * @protected
      */
   protected writeCore (path: string[], value: string): Node {
-    const index = parseInt(path.shift() as string)
+    let index = parseInt(path.shift() as string)
     if (index < 1) {
       throw new Error("Can't have an index < 1")
     }
+    if (this._name === 'MSH') {
+      if (index === 1 || index === 2) {
+        throw new Error('You cannot assign the field separator or encoding characters')
+      } else {
+        index = index - 1
+      }
+    }
+
     return this.writeAtIndex(path, value, index)
   }