diff --git a/packages/grpc-js-core/src/call.ts b/packages/grpc-js-core/src/call.ts
index 5abc0479..87a8d9ae 100644
--- a/packages/grpc-js-core/src/call.ts
+++ b/packages/grpc-js-core/src/call.ts
@@ -7,16 +7,17 @@ import {Status} from './constants';
 import {Metadata} from './metadata';
 import {ObjectReadable, ObjectWritable} from './object-stream';
 
-export interface ServiceError extends Error {
+/**
+ * A type extending the built-in Error object with additional fields.
+ */
+export type ServiceError = {
   code?: number;
   metadata?: Metadata;
-}
-
-export class ServiceErrorImpl extends Error implements ServiceError {
-  code?: number;
-  metadata?: Metadata;
-}
+} & Error;
 
+/**
+ * A base type for all user-facing values returned by client-side method calls.
+ */
 export type Call = {
   cancel(): void;
   getPeer(): string;
@@ -24,16 +25,28 @@ export type Call = {
   & EmitterAugmentation1<'status', StatusObject>
   & EventEmitter;
 
+/**
+ * A type representing the return value of a unary method call.
+ */
 export type ClientUnaryCall = Call;
 
+/**
+ * A type representing the return value of a server stream method call.
+ */
 export type ClientReadableStream<ResponseType> = {
   deserialize: (chunk: Buffer) => ResponseType;
 } & Call & ObjectReadable<ResponseType>;
 
+/**
+ * A type representing the return value of a client stream method call.
+ */
 export type ClientWritableStream<RequestType> = {
   serialize: (value: RequestType) => Buffer;
 } & Call & ObjectWritable<RequestType>;
 
+/**
+ * A type representing the return value of a bidirectional stream method call.
+ */
 export type ClientDuplexStream<RequestType, ResponseType> =
   ClientWritableStream<RequestType> & ClientReadableStream<ResponseType>;
 
@@ -78,7 +91,7 @@ function setUpReadableStream<ResponseType>(
   call.on('status', (status: StatusObject) => {
     stream.emit('status', status);
     if (status.code !== Status.OK) {
-      const error = new ServiceErrorImpl(status.details);
+      const error: ServiceError = new Error(status.details);
       error.code = status.code;
       error.metadata = status.metadata;
       stream.emit('error', error);
diff --git a/packages/grpc-js-core/src/client.ts b/packages/grpc-js-core/src/client.ts
index 862d212c..ecfacccd 100644
--- a/packages/grpc-js-core/src/client.ts
+++ b/packages/grpc-js-core/src/client.ts
@@ -1,7 +1,7 @@
 import {once} from 'lodash';
 import {URL} from 'url';
 
-import {ClientDuplexStream, ClientDuplexStreamImpl, ClientReadableStream, ClientReadableStreamImpl, ClientUnaryCall, ClientUnaryCallImpl, ClientWritableStream, ClientWritableStreamImpl, ServiceError, ServiceErrorImpl} from './call';
+import {ClientDuplexStream, ClientDuplexStreamImpl, ClientReadableStream, ClientReadableStreamImpl, ClientUnaryCall, ClientUnaryCallImpl, ClientWritableStream, ClientWritableStreamImpl, ServiceError} from './call';
 import {CallOptions, CallStream, StatusObject, WriteObject} from './call-stream';
 import {Channel, ChannelOptions, Http2Channel} from './channel';
 import {ChannelCredentials} from './channel-credentials';
@@ -83,7 +83,7 @@ export class Client {
       if (status.code === Status.OK) {
         callback(null, responseMessage as ResponseType);
       } else {
-        const error = new ServiceErrorImpl(status.details);
+        const error: ServiceError = new Error(status.details);
         error.code = status.code;
         error.metadata = status.metadata;
         callback(error);