diff --git a/qiskit_aer/utils/qobj_utils.py b/qiskit_aer/utils/qobj_utils.py
index 71dbbdffc..7b38190a8 100644
--- a/qiskit_aer/utils/qobj_utils.py
+++ b/qiskit_aer/utils/qobj_utils.py
@@ -14,90 +14,56 @@ IS ADDED TO QISKIT TERRA. THEY WILL NOT BE SUPPORTED AFTER THAT.
 
 import copy
 import numpy as np
-from qiskit.qobj import QobjItem
+from qiskit.qobj import QobjInstruction
 
 
-def qobj_append_item(qobj, exp_index, item):
-    """Append a QobjItem to a Qobj experiment.
+def append_instr(qobj, exp_index, instruction):
+    """Append a QobjInstruction to a QobjExperiment.
 
     Args:
-        qobj (Qobj): a Qobj object
-        exp_index (int): The index of the experiment in the qobj
-        item (QobjItem): The Qobj item to insert
+        qobj (Qobj): a Qobj object.
+        exp_index (int): The index of the experiment in the qobj.
+        instruction (QobjInstruction): instruction to insert.
     """
-    qobj.experiments[exp_index].instructions.append(item)
+    qobj.experiments[exp_index].instructions.append(instruction)
     return qobj
 
 
-def qobj_insert_item(qobj, exp_index, item, pos):
-    """Insert a QobjItem into a Qobj experiment.
+def insert_instr(qobj, exp_index, item, pos):
+    """Insert a QobjInstruction into a QobjExperiment.
 
     Args:
         qobj (Qobj): a Qobj object
-        exp_index (int): The index of the experiment in the qobj
-        item (QobjItem): The Qobj item to insert
+        exp_index (int): The index of the experiment in the qobj.
+        instruction(QobjInstruction): instruction to insert.
         pos (int): the position to insert the item.
     """
     qobj.experiments[exp_index].instructions.insert(pos, item)
     return qobj
 
 
-def qobj_get_item_positions(qobj, exp_index, name):
-    """Return all locations of QobjItem in a Qobj experiment.
+def get_instr_pos(qobj, exp_index, name):
+    """Return all locations of QobjInstruction in a Qobj experiment.
+
+    The return list is sorted in reverse order so iterating over it
+    to insert new items will work as expected.
 
     Args:
         qobj (Qobj): a Qobj object
         exp_index (int): The index of the experiment in the qobj
-        name (str): QobjItem name to find
+        name (str): QobjInstruction name to find
 
     Returns:
-        list[int]: A list of positions where the QobjItem is located.
+        list[int]: A list of positions where the QobjInstruction is located.
     """
     # Check only the name string of the item
-    return [i for i, val in enumerate(qobj.experiments[exp_index].instructions)
-            if val.name == name]
+    positions = [i for i, val in enumerate(qobj.experiments[exp_index].instructions)
+                 if val.name == name]
+    return positions
 
 
-def qobj_get_specific_item_positions(qobj, exp_index, item):
-    """Return all locations of QobjItem in a Qobj experiment.
-
-    Args:
-        qobj (Qobj): a Qobj object
-        exp_index (int): The index of the experiment in the qobj
-        item (QobjItem): The item to find
-
-    Returns:
-        list[int]: A list of positions where the QobjItem is located.
-    """
-    return [i for i, val in enumerate(qobj.experiments[exp_index].instructions)
-            if val == item]
-
-
-def qobj_insert_snapshots_after_barriers(qobj, snapshot):
-    """Insert a snapshot instruction after each barrier in qobj.
-
-    The label of the input snapshot will be appended with "i" where
-    "i" ranges from 0 to the 1 - number of barriers.
-
-    Args:
-        snapshot (QobjItem): a snapshot instruction.
-
-    Additional Information:
-    """
-    if snapshot.name != "snapshot":
-        raise ValueError("Invalid snapshot instruction")
-    label = snapshot.label
-    for exp_index in range(len(qobj.experiments)):
-        positions = qobj_get_item_positions(qobj, exp_index, "barrier")
-        for i, pos in reversed(list(enumerate(positions))):
-            item = copy.copy(snapshot)
-            item.label = label + "{}".format(i)
-            qobj_insert_item(qobj, exp_index, item, pos)
-    return qobj
-
-
-def qobj_unitary_item(mat, qubits, label=None):
-    """Create a unitary gate qobj item.
+def unitary_instr(mat, qubits, label=None):
+    """Create a unitary gate QobjInstruction.
 
     Args:
         mat (matrix_like): an n-qubit unitary matrix
@@ -105,7 +71,7 @@ def qobj_unitary_item(mat, qubits, label=None):
         label (str): optional string label for the untiary matrix
 
     Returns:
-        QobjItem: The qobj item for the unitary instruction.
+        QobjInstruction: The qobj item for the unitary instruction.
 
     Raises:
         ValueError: if the input matrix is not unitary
@@ -131,10 +97,38 @@ def qobj_unitary_item(mat, qubits, label=None):
                    "params": np.array(mat, dtype=complex)}
     if label is not None:
         instruction["label"] = str(label)
-    return QobjItem(**instruction)
+    return QobjInstruction(**instruction)
 
 
-def qobj_snapshot_item(snapshot_type, label, qubits=None, params=None):
+def measure_instr(qubits, memory, registers=None):
+    """Create a multi-qubit measure instruction"""
+    if len(qubits) != len(memory):
+        raise ValueError("Number of qubits does not match number of memory")
+    if registers is None:
+        return QobjInstruction(name='measure', qubits=qubits, memory=memory)
+    # Case where we also measure to registers
+    if len(qubits) != len(registers):
+        raise ValueError("Number of qubits does not match number of registers")
+    return QobjInstruction(name='measure', qubits=qubits, memory=memory,
+                           register=registers)
+
+
+def reset_instr(qubits):
+    """Create a multi-qubit reset instruction"""
+    return QobjInstruction(name='reset', qubits=qubits)
+
+
+def barrier_instr(num_qubits):
+    """Create a barrier QobjInstruction."""
+    return QobjInstruction(name='barrier', qubits=list(range(num_qubits)))
+
+
+def iden_instr(qubit):
+    """Create a barrier QobjInstruction."""
+    return QobjInstruction(name='id', qubits=[qubit])
+
+
+def snapshot_instr(snapshot_type, label, qubits=None, params=None):
     """Create a snapshot qobj item.
 
     Args:
@@ -145,7 +139,7 @@ def qobj_snapshot_item(snapshot_type, label, qubits=None, params=None):
                          See additional information.
 
     Returns:
-        QobjItem: The qobj item for the snapshot instruction.
+        QobjInstruction: The qobj item for the snapshot instruction.
 
 
     Additional Information:
@@ -184,32 +178,28 @@ def qobj_snapshot_item(snapshot_type, label, qubits=None, params=None):
         snap["name"] = "expval_matrix"
         snap["params"] = [[1.0, qubits, params]]
     # TODO: implicit conversion for Pauli expval params
-    return QobjItem(**snap)
+    return QobjInstruction(**snap)
 
 
-def qobj_measure_item(qubits, memory, registers=None):
-    """Create a multi-qubit measure instruction"""
-    if len(qubits) != len(memory):
-        raise ValueError("Number of qubits does not match number of memory")
-    if registers is None:
-        return QobjItem(name='measure', qubits=qubits, memory=memory)
-    # Case where we also measure to registers
-    if len(qubits) != len(registers):
-        raise ValueError("Number of qubits does not match number of registers")
-    return QobjItem(name='measure', qubits=qubits, memory=memory,
-                    register=registers)
+def insert_snapshots_after_barriers(qobj, snapshot):
+    """Insert a snapshot instruction after each barrier in qobj.
 
+    The label of the input snapshot will be appended with "i" where
+    "i" ranges from 0 to the 1 - number of barriers.
 
-def qobj_reset_item(qubits):
-    """Create a multi-qubit reset instruction"""
-    return QobjItem(name='reset', qubits=qubits)
+    Args:
+        qobj (Qobj): a qobj to insert snapshots into
+        snapshot (QobjInstruction): a snapshot instruction.
 
-
-def qobj_barrier_item(num_qubits):
-    """Create a barrier QobjItem."""
-    return QobjItem(name='barrier', qubits=list(range(num_qubits)))
-
-
-def qobj_iden_item(qubit):
-    """Create a barrier QobjItem."""
-    return QobjItem(name='id', qubits=[qubit])
+    Additional Information:
+    """
+    if snapshot.name != "snapshot":
+        raise ValueError("Invalid snapshot instruction")
+    label = snapshot.label
+    for exp_index in range(len(qobj.experiments)):
+        positions = get_instr_pos(qobj, exp_index, "barrier")
+        for i, pos in reversed(list(enumerate(positions))):
+            item = copy.copy(snapshot)
+            item.label = label + "{}".format(i)
+            insert_instr(qobj, exp_index, item, pos)
+    return qobj
diff --git a/test/terra/test_noise_model.py b/test/terra/test_noise_model.py
index 4c63013de..1501e806d 100644
--- a/test/terra/test_noise_model.py
+++ b/test/terra/test_noise_model.py
@@ -13,12 +13,13 @@ import unittest
 from test.terra.utils import common
 from qiskit import QuantumRegister, ClassicalRegister, QuantumCircuit
 from qiskit import compile
-from qiskit_aer.noise import NoiseModel, QuantumError
 from qiskit_aer.backends import QasmSimulator
+from qiskit_aer.noise import NoiseModel
+from qiskit_aer.noise.errors.quantum_error import QuantumError
 from qiskit_aer.noise.errors.standard_errors import pauli_error
 from qiskit_aer.noise.errors.standard_errors import amplitude_damping_error
-from qiskit_aer.utils.qobj_utils import qobj_measure_item
-from qiskit_aer.utils.qobj_utils import qobj_append_item
+from qiskit_aer.utils.qobj_utils import measure_instr
+from qiskit_aer.utils.qobj_utils import append_instr
 
 
 class TestNoise(common.QiskitAerTestCase):
@@ -159,8 +160,8 @@ class TestNoise(common.QiskitAerTestCase):
         qobj = compile([circuit], backend, shots=shots,
                        basis_gates=noise_model.basis_gates)
         # Add measure to qobj
-        item = qobj_measure_item([0, 1], [0, 1])
-        qobj_append_item(qobj, 0, item)
+        item = measure_instr([0, 1], [0, 1])
+        append_instr(qobj, 0, item)
         # Execute
         result = backend.run(qobj, noise_model=noise_model).result()
         self.is_completed(result)
diff --git a/test/terra/test_quantum_error.py b/test/terra/test_quantum_error.py
index faa230cfb..c684467ab 100644
--- a/test/terra/test_quantum_error.py
+++ b/test/terra/test_quantum_error.py
@@ -13,7 +13,7 @@ import unittest
 from test.terra.utils import common
 import numpy as np
 from qiskit_aer.noise.noiseerror import NoiseError
-from qiskit_aer.noise.errors.readout_error import QuantumError
+from qiskit_aer.noise.errors.quantum_error import QuantumError
 from qiskit_aer.noise.errors.errorutils import standard_gate_unitary
 
 
diff --git a/test/terra/utils/ref_measure.py b/test/terra/utils/ref_measure.py
index b1f203936..a8faf83e2 100644
--- a/test/terra/utils/ref_measure.py
+++ b/test/terra/utils/ref_measure.py
@@ -17,9 +17,9 @@ from qiskit import QuantumRegister, ClassicalRegister, QuantumCircuit
 # direclty by qobj instructions until terra compiler supports them
 from qiskit import compile
 from qiskit_aer.backends import QasmSimulator
-from qiskit_aer.utils.qobj_utils import qobj_insert_item
-from qiskit_aer.utils.qobj_utils import qobj_measure_item
-from qiskit_aer.utils.qobj_utils import qobj_iden_item
+from qiskit_aer.utils.qobj_utils import insert_instr
+from qiskit_aer.utils.qobj_utils import measure_instr
+from qiskit_aer.utils.qobj_utils import iden_instr
 
 
 # ==========================================================================
@@ -182,9 +182,9 @@ def measure_circuits_qobj_deterministic(allow_sampling=True):
     circuit.x(qr[1])
     circuit.barrier(qr)
     qobj = compile(circuit, QasmSimulator(), shots=1)
-    qobj_insert_item(qobj, 0, qobj_measure_item([0, 1], [0, 1]), -1)
+    insert_instr(qobj, 0, measure_instr([0, 1], [0, 1]), -1)
     if not allow_sampling:
-        qobj_insert_item(qobj, 0, qobj_iden_item(0), -1)
+        insert_instr(qobj, 0, iden_instr(0), -1)
     final_qobj.experiments.append(qobj.experiments[0])
 
     # 3-qubit measure |101>
@@ -195,9 +195,9 @@ def measure_circuits_qobj_deterministic(allow_sampling=True):
     circuit.x(qr[2])
     circuit.barrier(qr)
     qobj = compile(circuit, QasmSimulator(), shots=1)
-    qobj_insert_item(qobj, 0, qobj_measure_item([0, 1, 2], [0, 1, 2]), -1)
+    insert_instr(qobj, 0, measure_instr([0, 1, 2], [0, 1, 2]), -1)
     if not allow_sampling:
-        qobj_insert_item(qobj, 0, qobj_iden_item(0), -1)
+        insert_instr(qobj, 0, iden_instr(0), -1)
     final_qobj.experiments.append(qobj.experiments[0])
 
     # 4-qubit measure |1010>
@@ -208,9 +208,9 @@ def measure_circuits_qobj_deterministic(allow_sampling=True):
     circuit.x(qr[3])
     circuit.barrier(qr)
     qobj = compile(circuit, QasmSimulator(), shots=1)
-    qobj_insert_item(qobj, 0, qobj_measure_item([0, 1, 2, 3], [0, 1, 2, 3]), -1)
+    insert_instr(qobj, 0, measure_instr([0, 1, 2, 3], [0, 1, 2, 3]), -1)
     if not allow_sampling:
-        qobj_insert_item(qobj, 0, qobj_iden_item(0), -1)
+        insert_instr(qobj, 0, iden_instr(0), -1)
     final_qobj.experiments.append(qobj.experiments[0])
 
     return final_qobj
@@ -264,9 +264,9 @@ def measure_circuits_qobj_nondeterministic(allow_sampling=True):
     circuit.h(qr[1])
     circuit.barrier(qr)
     qobj = compile(circuit, QasmSimulator(), shots=1)
-    qobj_insert_item(qobj, 0, qobj_measure_item([0, 1], [0, 1]), -1)
+    insert_instr(qobj, 0, measure_instr([0, 1], [0, 1]), -1)
     if not allow_sampling:
-        qobj_insert_item(qobj, 0, qobj_iden_item(0), -1)
+        insert_instr(qobj, 0, iden_instr(0), -1)
     final_qobj.experiments.append(qobj.experiments[0])
 
     # 3-qubit measure |++0>
@@ -277,9 +277,9 @@ def measure_circuits_qobj_nondeterministic(allow_sampling=True):
     circuit.h(qr[1])
     circuit.barrier(qr)
     qobj = compile(circuit, QasmSimulator(), shots=1)
-    qobj_insert_item(qobj, 0, qobj_measure_item([0, 1, 2], [0, 1, 2]), -1)
+    insert_instr(qobj, 0, measure_instr([0, 1, 2], [0, 1, 2]), -1)
     if not allow_sampling:
-        qobj_insert_item(qobj, 0, qobj_iden_item(0), -1)
+        insert_instr(qobj, 0, iden_instr(0), -1)
     final_qobj.experiments.append(qobj.experiments[0])
 
     return final_qobj
diff --git a/test/terra/utils/ref_unitary_gate.py b/test/terra/utils/ref_unitary_gate.py
index 83c7930bb..aa10d9e02 100644
--- a/test/terra/utils/ref_unitary_gate.py
+++ b/test/terra/utils/ref_unitary_gate.py
@@ -12,11 +12,10 @@ Test circuits and reference outputs for measure instruction.
 
 import numpy as np
 from qiskit import QuantumRegister, ClassicalRegister, QuantumCircuit, compile
-
 from qiskit_aer.backends import QasmSimulator
-from qiskit_aer.utils.qobj_utils import qobj_unitary_item
-from qiskit_aer.utils.qobj_utils import qobj_insert_item
-from qiskit_aer.utils.qobj_utils import qobj_measure_item
+from qiskit_aer.utils.qobj_utils import unitary_instr
+from qiskit_aer.utils.qobj_utils import append_instr
+from qiskit_aer.utils.qobj_utils import measure_instr
 
 
 # ==========================================================================
@@ -51,64 +50,64 @@ def unitary_gate_circuits_real_deterministic(final_measure=True):
     circuit = QuantumCircuit(*regs)
     circuit.barrier(qr)
     qobj = compile(circuit, QasmSimulator(), shots=1)
-    qobj_insert_item(qobj, 0, qobj_unitary_item(cx_mat, [0, 1]), -1)
+    append_instr(qobj, 0, unitary_instr(cx_mat, [0, 1]))
     if final_measure:
-        qobj_insert_item(qobj, 0, qobj_measure_item([0], [0]), -1)
-        qobj_insert_item(qobj, 0, qobj_measure_item([1], [1]), -1)
+        append_instr(qobj, 0, measure_instr([0], [0]))
+        append_instr(qobj, 0, measure_instr([1], [1]))
     final_qobj.experiments.append(qobj.experiments[0])
 
     # CX10, |00> state
     circuit = QuantumCircuit(*regs)
     circuit.barrier(qr)
     qobj = compile(circuit, QasmSimulator(), shots=1)
-    qobj_insert_item(qobj, 0, qobj_unitary_item(cx_mat, [1, 0]), -1)
+    append_instr(qobj, 0, unitary_instr(cx_mat, [1, 0]))
     if final_measure:
-        qobj_insert_item(qobj, 0, qobj_measure_item([0], [0]), -1)
-        qobj_insert_item(qobj, 0, qobj_measure_item([1], [1]), -1)
+        append_instr(qobj, 0, measure_instr([0], [0]))
+        append_instr(qobj, 0, measure_instr([1], [1]))
     final_qobj.experiments.append(qobj.experiments[0])
 
     # CX01.(X^I), |10> state
     circuit = QuantumCircuit(*regs)
     circuit.barrier(qr)
     qobj = compile(circuit, QasmSimulator(), shots=1)
-    qobj_insert_item(qobj, 0, qobj_unitary_item(x_mat, [1]), -1)
-    qobj_insert_item(qobj, 0, qobj_unitary_item(cx_mat, [0, 1]), -1)
+    append_instr(qobj, 0, unitary_instr(x_mat, [1]))
+    append_instr(qobj, 0, unitary_instr(cx_mat, [0, 1]))
     if final_measure:
-        qobj_insert_item(qobj, 0, qobj_measure_item([0], [0]), -1)
-        qobj_insert_item(qobj, 0, qobj_measure_item([1], [1]), -1)
+        append_instr(qobj, 0, measure_instr([0], [0]))
+        append_instr(qobj, 0, measure_instr([1], [1]))
     final_qobj.experiments.append(qobj.experiments[0])
 
     # CX10.(I^X), |01> state
     circuit = QuantumCircuit(*regs)
     circuit.barrier(qr)
     qobj = compile(circuit, QasmSimulator(), shots=1)
-    qobj_insert_item(qobj, 0, qobj_unitary_item(x_mat, [0]), -1)
-    qobj_insert_item(qobj, 0, qobj_unitary_item(cx_mat, [1, 0]), -1)
+    append_instr(qobj, 0, unitary_instr(x_mat, [0]))
+    append_instr(qobj, 0, unitary_instr(cx_mat, [1, 0]))
     if final_measure:
-        qobj_insert_item(qobj, 0, qobj_measure_item([0], [0]), -1)
-        qobj_insert_item(qobj, 0, qobj_measure_item([1], [1]), -1)
+        append_instr(qobj, 0, measure_instr([0], [0]))
+        append_instr(qobj, 0, measure_instr([1], [1]))
     final_qobj.experiments.append(qobj.experiments[0])
 
     # CX01.(I^X), |11> state
     circuit = QuantumCircuit(*regs)
     circuit.barrier(qr)
     qobj = compile(circuit, QasmSimulator(), shots=1)
-    qobj_insert_item(qobj, 0, qobj_unitary_item(x_mat, [0]), -1)
-    qobj_insert_item(qobj, 0, qobj_unitary_item(cx_mat, [0, 1]), -1)
+    append_instr(qobj, 0, unitary_instr(x_mat, [0]))
+    append_instr(qobj, 0, unitary_instr(cx_mat, [0, 1]))
     if final_measure:
-        qobj_insert_item(qobj, 0, qobj_measure_item([0], [0]), -1)
-        qobj_insert_item(qobj, 0, qobj_measure_item([1], [1]), -1)
+        append_instr(qobj, 0, measure_instr([0], [0]))
+        append_instr(qobj, 0, measure_instr([1], [1]))
     final_qobj.experiments.append(qobj.experiments[0])
 
     # CX10.(X^I), |11> state
     circuit = QuantumCircuit(*regs)
     circuit.barrier(qr)
     qobj = compile(circuit, QasmSimulator(), shots=1)
-    qobj_insert_item(qobj, 0, qobj_unitary_item(x_mat, [1]), -1)
-    qobj_insert_item(qobj, 0, qobj_unitary_item(cx_mat, [1, 0]), -1)
+    append_instr(qobj, 0, unitary_instr(x_mat, [1]))
+    append_instr(qobj, 0, unitary_instr(cx_mat, [1, 0]))
     if final_measure:
-        qobj_insert_item(qobj, 0, qobj_measure_item([0], [0]), -1)
-        qobj_insert_item(qobj, 0, qobj_measure_item([1], [1]), -1)
+        append_instr(qobj, 0, measure_instr([0], [0]))
+        append_instr(qobj, 0, measure_instr([1], [1]))
     final_qobj.experiments.append(qobj.experiments[0])
 
     return final_qobj
@@ -217,65 +216,64 @@ def unitary_gate_circuits_complex_deterministic(final_measure=True):
     circuit = QuantumCircuit(*regs)
     circuit.barrier(qr)
     qobj = compile(circuit, QasmSimulator(), shots=1)
-    qobj_insert_item(qobj, 0, qobj_unitary_item(cx_mat, [0, 1]), -1)
+    append_instr(qobj, 0, unitary_instr(cx_mat, [0, 1]))
     if final_measure:
-        qobj_insert_item(qobj, 0, qobj_measure_item([0], [0]), -1)
-        qobj_insert_item(qobj, 0, qobj_measure_item([1], [1]), -1)
+        append_instr(qobj, 0, measure_instr([0], [0]))
+        append_instr(qobj, 0, measure_instr([1], [1]))
     final_qobj.experiments.append(qobj.experiments[0])
 
     # CX10, |00> state
     circuit = QuantumCircuit(*regs)
     circuit.barrier(qr)
     qobj = compile(circuit, QasmSimulator(), shots=1)
-    qobj_insert_item(qobj, 0, qobj_unitary_item(cx_mat, [1, 0]), -1)
+    append_instr(qobj, 0, unitary_instr(cx_mat, [1, 0]))
     if final_measure:
-        qobj_insert_item(qobj, 0, qobj_measure_item([0], [0]), -1)
-        qobj_insert_item(qobj, 0, qobj_measure_item([1], [1]), -1)
+        append_instr(qobj, 0, measure_instr([0], [0]))
+        append_instr(qobj, 0, measure_instr([1], [1]))
     final_qobj.experiments.append(qobj.experiments[0])
 
-
     # CX01.(Y^I), |10> state
     circuit = QuantumCircuit(*regs)
     circuit.barrier(qr)
     qobj = compile(circuit, QasmSimulator(), shots=1)
-    qobj_insert_item(qobj, 0, qobj_unitary_item(y_mat, [1]), -1)
-    qobj_insert_item(qobj, 0, qobj_unitary_item(cx_mat, [0, 1]), -1)
+    append_instr(qobj, 0, unitary_instr(y_mat, [1]))
+    append_instr(qobj, 0, unitary_instr(cx_mat, [0, 1]))
     if final_measure:
-        qobj_insert_item(qobj, 0, qobj_measure_item([0], [0]), -1)
-        qobj_insert_item(qobj, 0, qobj_measure_item([1], [1]), -1)
+        append_instr(qobj, 0, measure_instr([0], [0]))
+        append_instr(qobj, 0, measure_instr([1], [1]))
     final_qobj.experiments.append(qobj.experiments[0])
 
     # CX10.(I^Y), |01> state
     circuit = QuantumCircuit(*regs)
     circuit.barrier(qr)
     qobj = compile(circuit, QasmSimulator(), shots=1)
-    qobj_insert_item(qobj, 0, qobj_unitary_item(y_mat, [0]), -1)
-    qobj_insert_item(qobj, 0, qobj_unitary_item(cx_mat, [1, 0]), -1)
+    append_instr(qobj, 0, unitary_instr(y_mat, [0]))
+    append_instr(qobj, 0, unitary_instr(cx_mat, [1, 0]))
     if final_measure:
-        qobj_insert_item(qobj, 0, qobj_measure_item([0], [0]), -1)
-        qobj_insert_item(qobj, 0, qobj_measure_item([1], [1]), -1)
+        append_instr(qobj, 0, measure_instr([0], [0]))
+        append_instr(qobj, 0, measure_instr([1], [1]))
     final_qobj.experiments.append(qobj.experiments[0])
 
     # CX01.(I^Y), |11> state
     circuit = QuantumCircuit(*regs)
     circuit.barrier(qr)
     qobj = compile(circuit, QasmSimulator(), shots=1)
-    qobj_insert_item(qobj, 0, qobj_unitary_item(y_mat, [0]), -1)
-    qobj_insert_item(qobj, 0, qobj_unitary_item(cx_mat, [0, 1]), -1)
+    append_instr(qobj, 0, unitary_instr(y_mat, [0]))
+    append_instr(qobj, 0, unitary_instr(cx_mat, [0, 1]))
     if final_measure:
-        qobj_insert_item(qobj, 0, qobj_measure_item([0], [0]), -1)
-        qobj_insert_item(qobj, 0, qobj_measure_item([1], [1]), -1)
+        append_instr(qobj, 0, measure_instr([0], [0]))
+        append_instr(qobj, 0, measure_instr([1], [1]))
     final_qobj.experiments.append(qobj.experiments[0])
 
     # CX10.(Y^I), |11> state
     circuit = QuantumCircuit(*regs)
     circuit.barrier(qr)
     qobj = compile(circuit, QasmSimulator(), shots=1)
-    qobj_insert_item(qobj, 0, qobj_unitary_item(y_mat, [1]), -1)
-    qobj_insert_item(qobj, 0, qobj_unitary_item(cx_mat, [1, 0]), -1)
+    append_instr(qobj, 0, unitary_instr(y_mat, [1]))
+    append_instr(qobj, 0, unitary_instr(cx_mat, [1, 0]))
     if final_measure:
-        qobj_insert_item(qobj, 0, qobj_measure_item([0], [0]), -1)
-        qobj_insert_item(qobj, 0, qobj_measure_item([1], [1]), -1)
+        append_instr(qobj, 0, measure_instr([0], [0]))
+        append_instr(qobj, 0, measure_instr([1], [1]))
     final_qobj.experiments.append(qobj.experiments[0])
 
     return final_qobj